Ewa Mosiniewicz - Academia.edu (original) (raw)

Papers by Ewa Mosiniewicz

Research paper thumbnail of FMR Investigation of In-Plane Magnetic Anisotropy and Interlayer Coupling in Fe/Si/Fe Trilayers

Materials Science Forum, 2001

ABSTRACT The in-plane magnetic anisotropy and interlayer coupling have been investigated in the F... more ABSTRACT The in-plane magnetic anisotropy and interlayer coupling have been investigated in the Fe/Si/Fe trilayers grown by de magnetron sputtering deposition on GaAs (001) substrates. The samples have been covered with thin Si cap layer. The measurements have been performed by means of ferromagnetic resonance (FMR) technique as a function of the orientation of dc magnetic field in plane of the film and at liquid helium and room temperatures. From these dependencies the in-plane cubic anisotropy constants as well as interlayer coupling constants are determined. It is shown that the uniaxial in-plane anisotropy has mainly magnetoelastic origin and directions of easy axes are different in both layers. Moreover, the anisotropy constants in both layers have different temperature dependencies related only to the differences in thermal expansion coefficients between Fe, Si and GaAs.

Research paper thumbnail of Combination of selol nanocapsules and magnetic hyperthermia hinders breast tumor growth in aged mice after a short-time treatment

Nanotechnology, 2022

Short time treatment with reduced dosages of selol-loaded PLGA nanocapsules (NcSel) combined with... more Short time treatment with reduced dosages of selol-loaded PLGA nanocapsules (NcSel) combined with magnetic hyperthermia (MHT) is evaluated in aged Erhlich tumor-bearing mice. Clinical, hematological, biochemical, genotoxic and histopathological parameters are assessed during 7 d treatment with NcSel and MHT, separately or combined. The time evolution of the tumor volume is successfully modeled using the logistic mathematical model. The combined therapy comprising NcSel and MHT is able to hinder primary tumor growth and a case of complete tumor remission is recorded. Moreover, no metastasis was diagnosed and the adverse effects are negligible. NcSel plus MHT may represent an effective and safe alternative to cancer control in aged patients. Future clinical trials are encouraged.

Research paper thumbnail of Decoration of a Poly(methyl vinyl ether-co-maleic anhydride)-Shelled Selol Nanocapsule with Folic Acid Increases Its Activity Against Different Cancer Cell Lines In Vitro

Journal of Nanoscience and Nanotechnology, 2018

Research paper thumbnail of Selol nanocapsules with a poly(methyl vinyl ether-co-maleic anhydride) shell conjugated to doxorubicin for combinatorial chemotherapy against murine breast adenocarcinoma in vivo

Artificial Cells, Nanomedicine, and Biotechnology, 2018

Research paper thumbnail of Magnetic studies of layer-by-layer assembled polyvinyl alcohol/iron oxide nanofilms

Physical chemistry chemical physics : PCCP, Jan 7, 2018

This study reports on investigation of the magnetic properties of layer-by-layer (LbL) assembled ... more This study reports on investigation of the magnetic properties of layer-by-layer (LbL) assembled nanofilms comprising polyvinyl alcohol (PVA) and citrate-coated magnetite (cit-MAG) nanoparticles deposited onto silicon (SF sample) and glass (GF sample) substrates. DC magnetization measurements were performed over the temperature range of 4 K to 300 K, in the applied magnetic field range of ±60 kOe. The magnetic data of the as-synthesized cit-MAG nanoparticles (F sample) are also collected for comparison. The three as-fabricated samples reveal perfect superparamagnetic (SPM) behavior only around room temperature; at temperatures lower than 200 K the SPM scaling is not observed and all samples behave as interacting superparamagnetic (ISPM) materials. The evolution from the ISPM to the SPM regime is marked by a steady decrease in the hysteretic properties of all samples, with the temperature-dependence of the coercivity decreasing slower than the T behavior predicted for non-interacting...

Research paper thumbnail of Nanocapsules for the co-delivery of selol and doxorubicin to breast adenocarcinoma 4T1 cells in vitro

Artificial cells, nanomedicine, and biotechnology, Jan 27, 2017

Nanocapsules (NCS-DOX) with an oily core of selol and a shell of poly(methyl vinyl ether-co-malei... more Nanocapsules (NCS-DOX) with an oily core of selol and a shell of poly(methyl vinyl ether-co-maleic anhydride) covalently conjugated to doxorubicin were developed. These nanocapsules are spherical, with an average hydrodynamic diameter of about 170 nm, and with negative zeta potential. NCS-DOX effectively co-delivered the selol and the doxorubicin into 4T1 cells and changed the intracellular distribution of DOX from the nuclei to the mitochondria. Moreover, a significantly increased cytotoxicity against 4T1 cells was observed, which is suggestive of additive or synergic effect of selol and doxorubicin. In conclusion, PVM/MA nanocapsules are suitable platforms to co-deliver drugs into cancer cells.

Research paper thumbnail of Upconversion fluorescence imaging of HeLa cells using ROS generating SiO2-coated lanthanide-doped NaYF4 nanoconstructs

RSC Advances, 2017

Multicolor upconversion of SiO2-coated nanoparticles using for cells imaging and reactive oxygen ... more Multicolor upconversion of SiO2-coated nanoparticles using for cells imaging and reactive oxygen species generation.

Research paper thumbnail of Antitumor activity and systemic effects of PVM/MA-shelled selol nanocapsules in lung adenocarcinoma-bearing mice

Nanotechnology, 2015

Selol is a semi-synthetic compound containing selenite that is effective against cancerous cells ... more Selol is a semi-synthetic compound containing selenite that is effective against cancerous cells and safer for clinical applications in comparison with other inorganic forms of selenite. Recently, we have developed a formulation of poly(methyl vinyl ether-co-maleic anhydride)-shelled selol nanocapsules (SPN), which reduced the proliferative activity of lung adenocarcinoma cells and presented little deleterious effects on normal cells in in vitro studies. In this study, we report on the antitumor activity and systemic effects induced by this formulation in chemically induced lung adenocarcinoma-bearing mice. The in vivo antitumor activity of the SPN was verified by macroscopic quantification, immunohistochemistry and morphological analyses. Toxicity analyses were performed by evaluations of the kidney, liver, and spleen; analyses of hemogram and plasma levels of alanine aminotransferase, aspartate transaminase, urea, and creatinine; and DNA fragmentation and cell cycle activity of the bone marrow cells. Furthermore, we investigated the potential of the SPN formulation to cause hemolysis, activate the complement system, provoke an inflammatory response and change the conformation of the plasma proteins. Our results showed that the SPN reduced the area of the surface tumor nodules but not the total number of tumor nodules. The biochemical and hematological findings were suggestive of the low systemic toxicity of the SPN formulation. The surface properties of the selol nanocapsules point to characteristics that are consistent with the treatment of the tumors in vivo: low hemolytic activity, weak inflammatory reaction with no activation of the complement system, and mild or absent conformational changes of the plasma proteins. In conclusion, this report suggests that the SPN formulation investigated herein exhibits anti-tumoral effects against lung adenocarcinoma in vivo and is associated with low systemic toxicity and high biocompatibility.

Research paper thumbnail of FMR Investigation of In-Plane Magnetic Anisotropy and Interlayer Coupling in Fe/Si/Fe Trilayers

Materials Science Forum, 2001

ABSTRACT The in-plane magnetic anisotropy and interlayer coupling have been investigated in the F... more ABSTRACT The in-plane magnetic anisotropy and interlayer coupling have been investigated in the Fe/Si/Fe trilayers grown by de magnetron sputtering deposition on GaAs (001) substrates. The samples have been covered with thin Si cap layer. The measurements have been performed by means of ferromagnetic resonance (FMR) technique as a function of the orientation of dc magnetic field in plane of the film and at liquid helium and room temperatures. From these dependencies the in-plane cubic anisotropy constants as well as interlayer coupling constants are determined. It is shown that the uniaxial in-plane anisotropy has mainly magnetoelastic origin and directions of easy axes are different in both layers. Moreover, the anisotropy constants in both layers have different temperature dependencies related only to the differences in thermal expansion coefficients between Fe, Si and GaAs.

Research paper thumbnail of Photomagnetic effect in the CdCr 2 Se 4 ferromagnetic semiconductor

Physical Review B, 1993

ABSTRACT The influence of infrared irradiation on the ferromagnetic resonance (FMR) of CdCr2Se4 s... more ABSTRACT The influence of infrared irradiation on the ferromagnetic resonance (FMR) of CdCr2Se4 single crystals has been investigated in the temperature range 4.2–130 K. It was found that the irradiation induced appreciable changes in the microwave conductivity, FMR line shape, FMR linewidth, and magnetocrystalline anisotropy of this material. These findings are discussed by taking into account three different mechanisms: the slow relaxation mechanism, the appearance of low-symmetry fields at the Cr2+ Jahn-Teller centers, and the skin effect.

Research paper thumbnail of Co-nanoencapsulation of magnetic nanoparticles and selol for breast tumor treatment: in vitro evaluation of cytotoxicity and magnetohyperthermia efficacy

International journal of nanomedicine, 2012

Antitumor activities have been described in selol, a hydrophobic mixture of molecules containing ... more Antitumor activities have been described in selol, a hydrophobic mixture of molecules containing selenium in their structure, and also in maghemite magnetic nanoparticles (MNPs). Both selol and MNPs were co-encapsulated within poly(lactic-co-glycolic acid) (PLGA) nanocapsules for therapeutic purposes. The PLGA-nanocapsules loaded with MNPs and selol were labeled MSE-NC and characterized by transmission and scanning electron microscopy, electrophoretic mobility, photon correlation spectroscopy, presenting a monodisperse profile, and positive charge. The antitumor effect of MSE-NC was evaluated using normal (MCF-10A) and neoplastic (4T1 and MCF-7) breast cell lines. Nanocapsules containing only MNPs or selol were used as control. MTT assay showed that the cytotoxicity induced by MSE-NC was dose and time dependent. Normal cells were less affected than tumor cells. Cell death occurred mainly by apoptosis. Further exposure of MSE-NC treated neoplastic breast cells to an alternating magne...

Research paper thumbnail of PVM/MA-shelled selol nanocapsules promote cell cycle arrest in A549 lung adenocarcinoma cells

Journal of Nanobiotechnology, 2014

Research paper thumbnail of Investigation of the Molecular Surface Coating on the Stability of Insulating Magnetic Oils

The Journal of Physical Chemistry C, 2010

Research paper thumbnail of Electron paramagnetic resonance of Gd3 in TlGdSe2

physica status solidi (a), 2003

ABSTRACT Electron paramagnetic resonance has been studied on the polycrystalline sample of the la... more ABSTRACT Electron paramagnetic resonance has been studied on the polycrystalline sample of the layer compound TlGdSe2. When the temperature is lowered from room temperature the linewidth reaches a shallow minimum near 60 K and then decreases rapidly below 15 K. From the two-dimensional molecular field model two exchange constants J1 and J2 with the nearest and next nearest neighbors were estimated. The calculated high-temperature limit of the linewidth (341 mT) is in fair agreement with the experimental value (314 mT). It may be slightly improved after taking into account the preferred orientation of the sample.

Research paper thumbnail of Influence of neutron irradiation on the magnetic properties of FeNiCrMoSiB amorphous alloys

Physica Status Solidi (a), 1988

Research paper thumbnail of Magnetic properties of Ni-complexes in a hydrazone structure

physica status solidi (a), 2003

ABSTRACT The Ni2+ complex with 5-methylsalicylaldehyde 5′-chlorosalicyloyl hydrazone has been stu... more ABSTRACT The Ni2+ complex with 5-methylsalicylaldehyde 5′-chlorosalicyloyl hydrazone has been studied with electron paramagnetic resonance spectrometer (EPR) and vibrating sample magnetometer (VSM) over the temperature range 2–300 K. The magnetization measurements, performed in the magnetic field of 1 T, show that at low temperatures the Ni2+ ions are coupled by the antiferromagnetic exchange interactions. Above the Néel temperature TN = 11.4 K, the temperature dependence of the susceptibility of Ni-complexes follows the Curie–Weiss law. The EPR spectrum observed at room temperature exhibits a broad signal originating from Ni2+ ions. It is also found that at low temperatures the EPR signal experiences a sharp broadening and shifts to the lower field region. The intensity of this signal decreases with lowering the temperature and below 11 K this line disappears. It may be attributed to the formation of an antiferromagnetically ordered phase at low temperatures.

Research paper thumbnail of EPR study of doped (Sr,Ca)10Cu17O29-type single crystals

Physica B: Condensed Matter, 2001

ABSTRACT We report on electron paramagnetic resonance (EPR) measurements on the quasi-one-dimensi... more ABSTRACT We report on electron paramagnetic resonance (EPR) measurements on the quasi-one-dimensional system (Sr,Ca)10Cu17O29, doped with Y, Bi, Pb and Al, which has simple chains and two-leg ladder chains of copper ions. A very broad absorption line, coming from the ladder chains, dominates near room temperature. The EPR signals observed below room temperature mainly come from the simple (dimerized) chains. A detailed analysis of the temperature dependencies of the resonance field, line width and intensity of EPR signal is presented. EPR spectra of Cu2+ ions located in chains are described in terms of Wannier excitons. It is also found that at low temperatures the EPR line experiences a sharp broadening and shifts to the lower field region. These findings are discussed by taking into account two different mechanisms: the magnetic dipole interactions among short-range ordered Cu2+ spins in the chains and the exchange interaction between Cu2+ ions located in chains and holes (“bottleneck effect”).

Research paper thumbnail of Synthesis and magnetic characterization of Pb1−xMnxS nanocrystals in glass matrix

Journal of Physics D: Applied Physics, 2008

The synthesis of manganese-doped PbS (Pb1-xMnxS) nanocrystal (NC) dots within a borosilicate glas... more The synthesis of manganese-doped PbS (Pb1-xMnxS) nanocrystal (NC) dots within a borosilicate glass matrix has been investigated by atomic force microscopy, electron paramagnetic resonance and magnetic measurements. The fusion method was employed in the preparation of the magnetic semiconductor NC dots whereas the measurements performed showed changes in the physical properties of the manganese-doped dots as a result of the

Research paper thumbnail of Magnetic Studies of Ferrofluid-Modified Microbial Cells

Journal of Nanoscience and Nanotechnology, 2010

Research paper thumbnail of Photoinduced changes in the ferromagnetic resonance of CdCr2Se4 single crystals

Journal of Magnetism and Magnetic Materials, 1992

ABSTRACT The effect of light irradiation on the ferromagnetic resonance of CdCr2Se4 single crysta... more ABSTRACT The effect of light irradiation on the ferromagnetic resonance of CdCr2Se4 single crystals have been investigated in the temperature range from 4.2 to 130 K. It was found that the irradiation induced appreciable changes in microwave conductivity, FMR lineshape and magnetocrystalline anisotropy of this material. These findings are discussed in terms of the possible light-induced creation of Cr2+ centres in the crystal.

Research paper thumbnail of FMR Investigation of In-Plane Magnetic Anisotropy and Interlayer Coupling in Fe/Si/Fe Trilayers

Materials Science Forum, 2001

ABSTRACT The in-plane magnetic anisotropy and interlayer coupling have been investigated in the F... more ABSTRACT The in-plane magnetic anisotropy and interlayer coupling have been investigated in the Fe/Si/Fe trilayers grown by de magnetron sputtering deposition on GaAs (001) substrates. The samples have been covered with thin Si cap layer. The measurements have been performed by means of ferromagnetic resonance (FMR) technique as a function of the orientation of dc magnetic field in plane of the film and at liquid helium and room temperatures. From these dependencies the in-plane cubic anisotropy constants as well as interlayer coupling constants are determined. It is shown that the uniaxial in-plane anisotropy has mainly magnetoelastic origin and directions of easy axes are different in both layers. Moreover, the anisotropy constants in both layers have different temperature dependencies related only to the differences in thermal expansion coefficients between Fe, Si and GaAs.

Research paper thumbnail of Combination of selol nanocapsules and magnetic hyperthermia hinders breast tumor growth in aged mice after a short-time treatment

Nanotechnology, 2022

Short time treatment with reduced dosages of selol-loaded PLGA nanocapsules (NcSel) combined with... more Short time treatment with reduced dosages of selol-loaded PLGA nanocapsules (NcSel) combined with magnetic hyperthermia (MHT) is evaluated in aged Erhlich tumor-bearing mice. Clinical, hematological, biochemical, genotoxic and histopathological parameters are assessed during 7 d treatment with NcSel and MHT, separately or combined. The time evolution of the tumor volume is successfully modeled using the logistic mathematical model. The combined therapy comprising NcSel and MHT is able to hinder primary tumor growth and a case of complete tumor remission is recorded. Moreover, no metastasis was diagnosed and the adverse effects are negligible. NcSel plus MHT may represent an effective and safe alternative to cancer control in aged patients. Future clinical trials are encouraged.

Research paper thumbnail of Decoration of a Poly(methyl vinyl ether-co-maleic anhydride)-Shelled Selol Nanocapsule with Folic Acid Increases Its Activity Against Different Cancer Cell Lines In Vitro

Journal of Nanoscience and Nanotechnology, 2018

Research paper thumbnail of Selol nanocapsules with a poly(methyl vinyl ether-co-maleic anhydride) shell conjugated to doxorubicin for combinatorial chemotherapy against murine breast adenocarcinoma in vivo

Artificial Cells, Nanomedicine, and Biotechnology, 2018

Research paper thumbnail of Magnetic studies of layer-by-layer assembled polyvinyl alcohol/iron oxide nanofilms

Physical chemistry chemical physics : PCCP, Jan 7, 2018

This study reports on investigation of the magnetic properties of layer-by-layer (LbL) assembled ... more This study reports on investigation of the magnetic properties of layer-by-layer (LbL) assembled nanofilms comprising polyvinyl alcohol (PVA) and citrate-coated magnetite (cit-MAG) nanoparticles deposited onto silicon (SF sample) and glass (GF sample) substrates. DC magnetization measurements were performed over the temperature range of 4 K to 300 K, in the applied magnetic field range of ±60 kOe. The magnetic data of the as-synthesized cit-MAG nanoparticles (F sample) are also collected for comparison. The three as-fabricated samples reveal perfect superparamagnetic (SPM) behavior only around room temperature; at temperatures lower than 200 K the SPM scaling is not observed and all samples behave as interacting superparamagnetic (ISPM) materials. The evolution from the ISPM to the SPM regime is marked by a steady decrease in the hysteretic properties of all samples, with the temperature-dependence of the coercivity decreasing slower than the T behavior predicted for non-interacting...

Research paper thumbnail of Nanocapsules for the co-delivery of selol and doxorubicin to breast adenocarcinoma 4T1 cells in vitro

Artificial cells, nanomedicine, and biotechnology, Jan 27, 2017

Nanocapsules (NCS-DOX) with an oily core of selol and a shell of poly(methyl vinyl ether-co-malei... more Nanocapsules (NCS-DOX) with an oily core of selol and a shell of poly(methyl vinyl ether-co-maleic anhydride) covalently conjugated to doxorubicin were developed. These nanocapsules are spherical, with an average hydrodynamic diameter of about 170 nm, and with negative zeta potential. NCS-DOX effectively co-delivered the selol and the doxorubicin into 4T1 cells and changed the intracellular distribution of DOX from the nuclei to the mitochondria. Moreover, a significantly increased cytotoxicity against 4T1 cells was observed, which is suggestive of additive or synergic effect of selol and doxorubicin. In conclusion, PVM/MA nanocapsules are suitable platforms to co-deliver drugs into cancer cells.

Research paper thumbnail of Upconversion fluorescence imaging of HeLa cells using ROS generating SiO2-coated lanthanide-doped NaYF4 nanoconstructs

RSC Advances, 2017

Multicolor upconversion of SiO2-coated nanoparticles using for cells imaging and reactive oxygen ... more Multicolor upconversion of SiO2-coated nanoparticles using for cells imaging and reactive oxygen species generation.

Research paper thumbnail of Antitumor activity and systemic effects of PVM/MA-shelled selol nanocapsules in lung adenocarcinoma-bearing mice

Nanotechnology, 2015

Selol is a semi-synthetic compound containing selenite that is effective against cancerous cells ... more Selol is a semi-synthetic compound containing selenite that is effective against cancerous cells and safer for clinical applications in comparison with other inorganic forms of selenite. Recently, we have developed a formulation of poly(methyl vinyl ether-co-maleic anhydride)-shelled selol nanocapsules (SPN), which reduced the proliferative activity of lung adenocarcinoma cells and presented little deleterious effects on normal cells in in vitro studies. In this study, we report on the antitumor activity and systemic effects induced by this formulation in chemically induced lung adenocarcinoma-bearing mice. The in vivo antitumor activity of the SPN was verified by macroscopic quantification, immunohistochemistry and morphological analyses. Toxicity analyses were performed by evaluations of the kidney, liver, and spleen; analyses of hemogram and plasma levels of alanine aminotransferase, aspartate transaminase, urea, and creatinine; and DNA fragmentation and cell cycle activity of the bone marrow cells. Furthermore, we investigated the potential of the SPN formulation to cause hemolysis, activate the complement system, provoke an inflammatory response and change the conformation of the plasma proteins. Our results showed that the SPN reduced the area of the surface tumor nodules but not the total number of tumor nodules. The biochemical and hematological findings were suggestive of the low systemic toxicity of the SPN formulation. The surface properties of the selol nanocapsules point to characteristics that are consistent with the treatment of the tumors in vivo: low hemolytic activity, weak inflammatory reaction with no activation of the complement system, and mild or absent conformational changes of the plasma proteins. In conclusion, this report suggests that the SPN formulation investigated herein exhibits anti-tumoral effects against lung adenocarcinoma in vivo and is associated with low systemic toxicity and high biocompatibility.

Research paper thumbnail of FMR Investigation of In-Plane Magnetic Anisotropy and Interlayer Coupling in Fe/Si/Fe Trilayers

Materials Science Forum, 2001

ABSTRACT The in-plane magnetic anisotropy and interlayer coupling have been investigated in the F... more ABSTRACT The in-plane magnetic anisotropy and interlayer coupling have been investigated in the Fe/Si/Fe trilayers grown by de magnetron sputtering deposition on GaAs (001) substrates. The samples have been covered with thin Si cap layer. The measurements have been performed by means of ferromagnetic resonance (FMR) technique as a function of the orientation of dc magnetic field in plane of the film and at liquid helium and room temperatures. From these dependencies the in-plane cubic anisotropy constants as well as interlayer coupling constants are determined. It is shown that the uniaxial in-plane anisotropy has mainly magnetoelastic origin and directions of easy axes are different in both layers. Moreover, the anisotropy constants in both layers have different temperature dependencies related only to the differences in thermal expansion coefficients between Fe, Si and GaAs.

Research paper thumbnail of Photomagnetic effect in the CdCr 2 Se 4 ferromagnetic semiconductor

Physical Review B, 1993

ABSTRACT The influence of infrared irradiation on the ferromagnetic resonance (FMR) of CdCr2Se4 s... more ABSTRACT The influence of infrared irradiation on the ferromagnetic resonance (FMR) of CdCr2Se4 single crystals has been investigated in the temperature range 4.2–130 K. It was found that the irradiation induced appreciable changes in the microwave conductivity, FMR line shape, FMR linewidth, and magnetocrystalline anisotropy of this material. These findings are discussed by taking into account three different mechanisms: the slow relaxation mechanism, the appearance of low-symmetry fields at the Cr2+ Jahn-Teller centers, and the skin effect.

Research paper thumbnail of Co-nanoencapsulation of magnetic nanoparticles and selol for breast tumor treatment: in vitro evaluation of cytotoxicity and magnetohyperthermia efficacy

International journal of nanomedicine, 2012

Antitumor activities have been described in selol, a hydrophobic mixture of molecules containing ... more Antitumor activities have been described in selol, a hydrophobic mixture of molecules containing selenium in their structure, and also in maghemite magnetic nanoparticles (MNPs). Both selol and MNPs were co-encapsulated within poly(lactic-co-glycolic acid) (PLGA) nanocapsules for therapeutic purposes. The PLGA-nanocapsules loaded with MNPs and selol were labeled MSE-NC and characterized by transmission and scanning electron microscopy, electrophoretic mobility, photon correlation spectroscopy, presenting a monodisperse profile, and positive charge. The antitumor effect of MSE-NC was evaluated using normal (MCF-10A) and neoplastic (4T1 and MCF-7) breast cell lines. Nanocapsules containing only MNPs or selol were used as control. MTT assay showed that the cytotoxicity induced by MSE-NC was dose and time dependent. Normal cells were less affected than tumor cells. Cell death occurred mainly by apoptosis. Further exposure of MSE-NC treated neoplastic breast cells to an alternating magne...

Research paper thumbnail of PVM/MA-shelled selol nanocapsules promote cell cycle arrest in A549 lung adenocarcinoma cells

Journal of Nanobiotechnology, 2014

Research paper thumbnail of Investigation of the Molecular Surface Coating on the Stability of Insulating Magnetic Oils

The Journal of Physical Chemistry C, 2010

Research paper thumbnail of Electron paramagnetic resonance of Gd3 in TlGdSe2

physica status solidi (a), 2003

ABSTRACT Electron paramagnetic resonance has been studied on the polycrystalline sample of the la... more ABSTRACT Electron paramagnetic resonance has been studied on the polycrystalline sample of the layer compound TlGdSe2. When the temperature is lowered from room temperature the linewidth reaches a shallow minimum near 60 K and then decreases rapidly below 15 K. From the two-dimensional molecular field model two exchange constants J1 and J2 with the nearest and next nearest neighbors were estimated. The calculated high-temperature limit of the linewidth (341 mT) is in fair agreement with the experimental value (314 mT). It may be slightly improved after taking into account the preferred orientation of the sample.

Research paper thumbnail of Influence of neutron irradiation on the magnetic properties of FeNiCrMoSiB amorphous alloys

Physica Status Solidi (a), 1988

Research paper thumbnail of Magnetic properties of Ni-complexes in a hydrazone structure

physica status solidi (a), 2003

ABSTRACT The Ni2+ complex with 5-methylsalicylaldehyde 5′-chlorosalicyloyl hydrazone has been stu... more ABSTRACT The Ni2+ complex with 5-methylsalicylaldehyde 5′-chlorosalicyloyl hydrazone has been studied with electron paramagnetic resonance spectrometer (EPR) and vibrating sample magnetometer (VSM) over the temperature range 2–300 K. The magnetization measurements, performed in the magnetic field of 1 T, show that at low temperatures the Ni2+ ions are coupled by the antiferromagnetic exchange interactions. Above the Néel temperature TN = 11.4 K, the temperature dependence of the susceptibility of Ni-complexes follows the Curie–Weiss law. The EPR spectrum observed at room temperature exhibits a broad signal originating from Ni2+ ions. It is also found that at low temperatures the EPR signal experiences a sharp broadening and shifts to the lower field region. The intensity of this signal decreases with lowering the temperature and below 11 K this line disappears. It may be attributed to the formation of an antiferromagnetically ordered phase at low temperatures.

Research paper thumbnail of EPR study of doped (Sr,Ca)10Cu17O29-type single crystals

Physica B: Condensed Matter, 2001

ABSTRACT We report on electron paramagnetic resonance (EPR) measurements on the quasi-one-dimensi... more ABSTRACT We report on electron paramagnetic resonance (EPR) measurements on the quasi-one-dimensional system (Sr,Ca)10Cu17O29, doped with Y, Bi, Pb and Al, which has simple chains and two-leg ladder chains of copper ions. A very broad absorption line, coming from the ladder chains, dominates near room temperature. The EPR signals observed below room temperature mainly come from the simple (dimerized) chains. A detailed analysis of the temperature dependencies of the resonance field, line width and intensity of EPR signal is presented. EPR spectra of Cu2+ ions located in chains are described in terms of Wannier excitons. It is also found that at low temperatures the EPR line experiences a sharp broadening and shifts to the lower field region. These findings are discussed by taking into account two different mechanisms: the magnetic dipole interactions among short-range ordered Cu2+ spins in the chains and the exchange interaction between Cu2+ ions located in chains and holes (“bottleneck effect”).

Research paper thumbnail of Synthesis and magnetic characterization of Pb1−xMnxS nanocrystals in glass matrix

Journal of Physics D: Applied Physics, 2008

The synthesis of manganese-doped PbS (Pb1-xMnxS) nanocrystal (NC) dots within a borosilicate glas... more The synthesis of manganese-doped PbS (Pb1-xMnxS) nanocrystal (NC) dots within a borosilicate glass matrix has been investigated by atomic force microscopy, electron paramagnetic resonance and magnetic measurements. The fusion method was employed in the preparation of the magnetic semiconductor NC dots whereas the measurements performed showed changes in the physical properties of the manganese-doped dots as a result of the

Research paper thumbnail of Magnetic Studies of Ferrofluid-Modified Microbial Cells

Journal of Nanoscience and Nanotechnology, 2010

Research paper thumbnail of Photoinduced changes in the ferromagnetic resonance of CdCr2Se4 single crystals

Journal of Magnetism and Magnetic Materials, 1992

ABSTRACT The effect of light irradiation on the ferromagnetic resonance of CdCr2Se4 single crysta... more ABSTRACT The effect of light irradiation on the ferromagnetic resonance of CdCr2Se4 single crystals have been investigated in the temperature range from 4.2 to 130 K. It was found that the irradiation induced appreciable changes in microwave conductivity, FMR lineshape and magnetocrystalline anisotropy of this material. These findings are discussed in terms of the possible light-induced creation of Cr2+ centres in the crystal.