J. Lago - Academia.edu (original) (raw)

Papers by J. Lago

Research paper thumbnail of Spin dynamics in the molecular antiferromagnetic ring Cr7Ni from 1H NMR

Research paper thumbnail of magnet LiYF4:Ho 3

Temperature and magnetic field dependences of the 19F nuclear spin-lattice relaxation in a single... more Temperature and magnetic field dependences of the 19F nuclear spin-lattice relaxation in a single crystal of LiYF4 doped with holmium are described by an approach based on a detailed consideration of the magnetic dipole-dipole interactions between nuclei and impurity paramagnetic ions and nuclear spin diffusion processes. The observed non- exponential long time recovery of the nuclear magnetization after saturation at

Research paper thumbnail of ChemInform Abstract: Crystal and Magnetic Structures of Ca4Mn3O10, an n = 3 Ruddlesden-Popper (RP) Compound

Research paper thumbnail of Er2Ti2O7: Evidence of quantum order by disorder in a frustrated antiferromagnet

PHYSICAL REVIEW B, 2003

Er2Ti2O7 has been suggested to be a realization of the frustrated 111 XY pyrochlore lattice antif... more Er2Ti2O7 has been suggested to be a realization of the frustrated 111 XY pyrochlore lattice antiferromagnet, for which theory predicts fluctuation-induced symmetry breaking in a highly degenerate ground state manifold. We present a theoretical analysis of the classical model compared to neutron scattering experiments on the real material, both below and above TN =1.173(2) K. The model correctly predicts the ordered magnetic structure, suggesting that the real system has order stabilized by zero-point quantum fluctuations that can be modelled by classical spin wave theory. However, the model fails to describe the excitations of the system, which show unusual features. PACS numbers: 28.20.Cz, 75.25.+z An important aspect of condensed matter is the separation of energy scales, such that the minimization of one set of interactions may result in the frustration of another. A paradigm is the frustrated antiferromagnet, in which the local magnetic couplings between ions are frustrated by the crystal symmetry that the ions adopt. However, a systematic study of the rare earth pyrochlore titanates R 2 Ti 2 O 7 has shown that local antiferromagnetic bond frustration is neither a necessary, nor a sufficient condition for magnetic frustration 1,2,3,4,5 . Rather, it arises from the interplay, in the context of the crystal symmetry, of the principal terms in the spin Hamiltonian. In the case of R 2 Ti 2 O 7 , the main terms are single-ion anisotropy, exchange and dipolar coupling. Depending on the balance of these factors, one observes spin ice behavior (R = Ho, Dy) 1,2,3 , spin liquid behavior (R = Tb) 4 , and dipole induced partial order (R = Gd) 5 .

Research paper thumbnail of Chemistry of the Naturally Layered Manganites: Prospects for New Materials

Magnetics International Conference, 1998

Research paper thumbnail of Muon Spin Rotation Studies of Spin Dynamics at Avoided Level Crossings in LiY0.998Ho0.002F4

Physical Review Letters, 2007

PACS numbers: 75.45.+j, 76.60.Es, 71.70.Jp, 76.30.Kg We have studied the Ho 3+ spin dynamics for ... more PACS numbers: 75.45.+j, 76.60.Es, 71.70.Jp, 76.30.Kg We have studied the Ho 3+ spin dynamics for LiY 0.998 Ho 0.002 F 4 through the positive muon (μ + ) transverse field depolarization rate TF as a function of temperature and magnetic field. We find sharp reductions in ( ) H TF at fields of 23, 46 and 69 mT, for which the Ho 3+ ion system has field-induced (avoided) level crossings. The reduction scales with calculated level repulsions, suggesting that μ + depolarization by slow fluctuations of non-resonant Ho 3+ spin states is partially suppressed when resonant tunneling opens new fluctuation channels at frequencies much greater than the muon precession frequency.

Research paper thumbnail of Magnetic order, magnetic correlations, and spin dynamics in the pyrochlore antiferromagnet Er_{2}Ti_{2}O_{7}

Research paper thumbnail of Dynamics of diluted Ho spin ice Ho2−xYxTi2O7 studied by neutron spin echo spectroscopy and ac susceptibility

Physical Review B, 2006

We have studied the spin relaxation in diluted spin ice Ho 2− x Y x Ti 2 O 7 by means of neutron ... more We have studied the spin relaxation in diluted spin ice Ho 2− x Y x Ti 2 O 7 by means of neutron spin echo spectroscopy and ac susceptibility measurements. Remarkably, the geometrical frustration is not relieved by doping with nonmagnetic Y, and the dynamics of ...

Research paper thumbnail of Non-adiabatic small polaron hopping in the n = 3 Ruddlesden–Popper compound Ca 4 Mn 3 O 10

Journal of Physics: Condensed Matter, 2003

Research paper thumbnail of Weak ferromagnetism and spin-glass behaviour of the n = 3 Ruddlesden-Popper compound Ca 4 Mn 3 O 10 : a dc magnetization study

Journal of Physics: Condensed Matter, 2000

Research paper thumbnail of Physical properties of the n =3 Ruddlesden - Popper compound

Journal of Physics: Condensed Matter, 1998

... AI Mihut†, LE Spring†, RI Bewley†, SJ Blundell†, W Hayes†, Th Jestädt†, BW Lovett†, R McDonal... more ... AI Mihut†, LE Spring†, RI Bewley†, SJ Blundell†, W Hayes†, Th Jestädt†, BW Lovett†, R McDonald†, FL Pratt†, J Singleton†, PD Battle‡, J ... proportional to the square of the magnetization, and is largest at low temperatures; a 40% drop in resistivity is observed in a magnetic field ...

Research paper thumbnail of Magnetization and spin dynamics of a Cr-based magnetic cluster

Journal of Magnetism and Magnetic Materials, 2010

We study the magnetization and the spin dynamics of the Cr7Ni ring-shaped magnetic cluster. Measu... more We study the magnetization and the spin dynamics of the Cr7Ni ring-shaped magnetic cluster. Measurements of the magnetization at high pulsed fields and low temperature are compared to calculations and show that the spin Hamiltonian approach provides a good description of Cr7Ni magnetic molecule. In addition, the phonon-induced relaxation dynamics of molecular observables has been investigated. By assuming the spin-phonon coupling to take place through the modulation of the local crystal fields, it is possible to evaluate the decay of fluctuations of two generic molecular observables. The nuclear spin-lattice relaxation rate 1/T1 directly probes such fluctuations, and allows to determine the magnetoelastic coupling strength.

Research paper thumbnail of Evaluation of a methylation procedure to determine cyclopropenoids fatty acids from Sterculia striata St. Hil. Et Nauds seed oil

Journal of Chromatography A, 2004

Cyclopropenoids fatty acids (CPFA) from Sterculia striata seed oil were characterized by gas chro... more Cyclopropenoids fatty acids (CPFA) from Sterculia striata seed oil were characterized by gas chromatography/mass spectrometry (GC/MS) and quantified by gas chromatography-flame ionization detector (GC-FID) after derivation to fatty acid methyl esters using a cold basecatalyzed procedure. 1 H nuclear magnetic resonance (NMR) analysis were done in oil and fatty acid methyl esters derivatives to quantify CPFA and verify artifacts formation during the base-catalyzed reaction. Similar quantities of CPFA were found in S. striata and Sterculia foetida seed oils before and after a base-catalyzed methylation by NMR analysis, with no artifact formation. These results were compatible with those obtained by GC-FID analysis. Transmethylation with KOH in methanol was an appropriated method to prepare cyclopropenoids fatty acids methyl esters and quantify them by GC and NMR analysis.

Research paper thumbnail of Local spin dynamics in magnetic molecular chains studied by NMR and μSR

Inorganica Chimica Acta, 2007

We present NMR and l + SR study of spin dynamics in one-dimensional and quasi-one-dimensional mol... more We present NMR and l + SR study of spin dynamics in one-dimensional and quasi-one-dimensional molecular magnets of recent synthesis. In particular, we focus on the so called Gd(hfac) 3 NIT-R and CoPhOMe magnetic chains families. For Gd-R helimagnets we show some differences between ''weakly frustrated systems'' and ''fully frustrated systems''. The different behaviour is due to the different radical inserted in the chains (R = Me, Ph for ''weakly frustrated systems'' and R = iPr, Et for ''fully frustrated systems''). The existence of different phase transitions, particularly to 3D long-range magnetic order in Gd-Ph and to chiral order in Gd-iPr, is remarked together with a comparison between results obtained from macroscopic and microscopic investigating techniques. As regards CoPhOMe slowly relaxing chain, the 1 H NMR measurements confirm the freezing of the spins at low temperature, which prevents the 3D long-range order, and display the presence of two relaxation mechanisms related to distinct contributions to the local spin relaxation.

Research paper thumbnail of 19F nuclear spin relaxation and spin diffusion effects in the single-ion magnet LiYF4:Ho3+

The European Physical Journal B, 2008

Temperature and magnetic field dependences of the 19 F nuclear spin-lattice relaxation in a singl... more Temperature and magnetic field dependences of the 19 F nuclear spin-lattice relaxation in a single crystal of LiYF 4 doped with holmium are described by an approach based on a detailed consideration of the magnetic dipole-dipole interactions between nuclei and impurity paramagnetic ions and nuclear spin diffusion processes. The observed nonexponential long time recovery of the nuclear magnetization after saturation at intermediate temperatures is in agreement with predictions of the spin-diffusion theory in a case of the diffusion limited relaxation. At avoided level crossings in the spectrum of electron-nuclear states of Ho 3+ ions, rates of nuclear spin-lattice relaxation increase due to quasi-resonant energy exchange between nuclei and paramagnetic ions in contrast to the predominant role played by electronic cross-relaxation processes in the low-frequency ac-susceptibility. PACS. 76.60.-k Nuclear magnetic resonance and relaxation -75.40.Gb Dynamic properties -76.30.Kg Magnetic resonances and relaxations in condensed matter Rare-earth ions and impurities __________________________________________ a

Research paper thumbnail of Sesquiterpenes, diterpenes, steroids and alkaloid from branches of Xylopia brasiliensis Spreng (Annonaceae)

Biochemical Systematics and Ecology, 2005

RefDoc Bienvenue - Welcome. Refdoc est un service / is powered by. ...

Research paper thumbnail of μSR investigation of spin dynamics in pure and Zn-doped Co (hfac) 2NITPhOMe single-chain magnet

Research paper thumbnail of Low-energy spin dynamics in the giant keplerate molecule {Mo72Fe30}: A muon spin relaxation and H1 NMR investigation

Physical Review B, 2007

We present muon spin relaxation and H1 NMR results on the magnetically frustrated keplerate molec... more We present muon spin relaxation and H1 NMR results on the magnetically frustrated keplerate molecule {Mo72Fe30} , aimed at studying the local spin dynamics as a function of temperature. We find that, in common with other molecular magnets, the relaxation spectrum of this material is characterized by a single dominating electronic correlation time tau . Experiments and theory show that tau has a thermally activated behavior with an activation gap of the order of the energy difference between the lowest-lying rotational bands in this material. This shows that, in the intermediate temperature range just above 1K , the relaxation of the electronic spin system occurs via Orbach processes involving energy levels belonging to the two lowest-lying rotational bands. Our data thus provide an experimental estimate of the first interband gap.

Research paper thumbnail of Phonon-induced relaxation in the Cr_{7}Ni magnetic molecule probed by NMR

Physical Review B, 2010

We study the phonon-induced relaxation dynamics in the heterometallic Cr7Ni ring. By assuming tha... more We study the phonon-induced relaxation dynamics in the heterometallic Cr7Ni ring. By assuming that spin-phonon coupling occurs through the modulation of local crystal fields, we investigate the decay of time correlations of molecular observables, such as fluctuations of the cluster magnetization. Single-crystal H1 nuclear magnetic resonance measurements have been performed for two orthogonal orientations of the applied magnetic field. The

Research paper thumbnail of Glassy dynamics in the low-temperature inhomogeneous ferromagnetic phase of the quantum spin ice Yb<span class="aps-inline-formula"><math><msub><mrow></mrow><mn>2</mn></msub></math></span>Sn<span class="aps-inline-formula"><math><msub><mrow></mrow><mn>2</mn></msub></math></span>O<span class="aps-...

Physical Review B, 2014

Here we present a detailed muon spin relaxation (μSR), neutron diffraction, and ac-susceptibility... more Here we present a detailed muon spin relaxation (μSR), neutron diffraction, and ac-susceptibility study of Yb 2 Sn 2 O 7 that shows that despite the onset of ferromagnetic long-range order at T c ≈ 0.140 K, the lowtemperature phase of this material remains highly disordered with glassy dynamics that span various frequency decades. We suggest that the observed disordered ground state might be made of infinite, percolating clusters coexisting with smaller ones. This mesoscopic cluster glass state would be the result of the enhanced effect of even a small amount of disorder, capable of disrupting the "clean" ordered state near a quantum critical point.

Research paper thumbnail of Spin dynamics in the molecular antiferromagnetic ring Cr7Ni from 1H NMR

Research paper thumbnail of magnet LiYF4:Ho 3

Temperature and magnetic field dependences of the 19F nuclear spin-lattice relaxation in a single... more Temperature and magnetic field dependences of the 19F nuclear spin-lattice relaxation in a single crystal of LiYF4 doped with holmium are described by an approach based on a detailed consideration of the magnetic dipole-dipole interactions between nuclei and impurity paramagnetic ions and nuclear spin diffusion processes. The observed non- exponential long time recovery of the nuclear magnetization after saturation at

Research paper thumbnail of ChemInform Abstract: Crystal and Magnetic Structures of Ca4Mn3O10, an n = 3 Ruddlesden-Popper (RP) Compound

Research paper thumbnail of Er2Ti2O7: Evidence of quantum order by disorder in a frustrated antiferromagnet

PHYSICAL REVIEW B, 2003

Er2Ti2O7 has been suggested to be a realization of the frustrated 111 XY pyrochlore lattice antif... more Er2Ti2O7 has been suggested to be a realization of the frustrated 111 XY pyrochlore lattice antiferromagnet, for which theory predicts fluctuation-induced symmetry breaking in a highly degenerate ground state manifold. We present a theoretical analysis of the classical model compared to neutron scattering experiments on the real material, both below and above TN =1.173(2) K. The model correctly predicts the ordered magnetic structure, suggesting that the real system has order stabilized by zero-point quantum fluctuations that can be modelled by classical spin wave theory. However, the model fails to describe the excitations of the system, which show unusual features. PACS numbers: 28.20.Cz, 75.25.+z An important aspect of condensed matter is the separation of energy scales, such that the minimization of one set of interactions may result in the frustration of another. A paradigm is the frustrated antiferromagnet, in which the local magnetic couplings between ions are frustrated by the crystal symmetry that the ions adopt. However, a systematic study of the rare earth pyrochlore titanates R 2 Ti 2 O 7 has shown that local antiferromagnetic bond frustration is neither a necessary, nor a sufficient condition for magnetic frustration 1,2,3,4,5 . Rather, it arises from the interplay, in the context of the crystal symmetry, of the principal terms in the spin Hamiltonian. In the case of R 2 Ti 2 O 7 , the main terms are single-ion anisotropy, exchange and dipolar coupling. Depending on the balance of these factors, one observes spin ice behavior (R = Ho, Dy) 1,2,3 , spin liquid behavior (R = Tb) 4 , and dipole induced partial order (R = Gd) 5 .

Research paper thumbnail of Chemistry of the Naturally Layered Manganites: Prospects for New Materials

Magnetics International Conference, 1998

Research paper thumbnail of Muon Spin Rotation Studies of Spin Dynamics at Avoided Level Crossings in LiY0.998Ho0.002F4

Physical Review Letters, 2007

PACS numbers: 75.45.+j, 76.60.Es, 71.70.Jp, 76.30.Kg We have studied the Ho 3+ spin dynamics for ... more PACS numbers: 75.45.+j, 76.60.Es, 71.70.Jp, 76.30.Kg We have studied the Ho 3+ spin dynamics for LiY 0.998 Ho 0.002 F 4 through the positive muon (μ + ) transverse field depolarization rate TF as a function of temperature and magnetic field. We find sharp reductions in ( ) H TF at fields of 23, 46 and 69 mT, for which the Ho 3+ ion system has field-induced (avoided) level crossings. The reduction scales with calculated level repulsions, suggesting that μ + depolarization by slow fluctuations of non-resonant Ho 3+ spin states is partially suppressed when resonant tunneling opens new fluctuation channels at frequencies much greater than the muon precession frequency.

Research paper thumbnail of Magnetic order, magnetic correlations, and spin dynamics in the pyrochlore antiferromagnet Er_{2}Ti_{2}O_{7}

Research paper thumbnail of Dynamics of diluted Ho spin ice Ho2−xYxTi2O7 studied by neutron spin echo spectroscopy and ac susceptibility

Physical Review B, 2006

We have studied the spin relaxation in diluted spin ice Ho 2− x Y x Ti 2 O 7 by means of neutron ... more We have studied the spin relaxation in diluted spin ice Ho 2− x Y x Ti 2 O 7 by means of neutron spin echo spectroscopy and ac susceptibility measurements. Remarkably, the geometrical frustration is not relieved by doping with nonmagnetic Y, and the dynamics of ...

Research paper thumbnail of Non-adiabatic small polaron hopping in the n = 3 Ruddlesden–Popper compound Ca 4 Mn 3 O 10

Journal of Physics: Condensed Matter, 2003

Research paper thumbnail of Weak ferromagnetism and spin-glass behaviour of the n = 3 Ruddlesden-Popper compound Ca 4 Mn 3 O 10 : a dc magnetization study

Journal of Physics: Condensed Matter, 2000

Research paper thumbnail of Physical properties of the n =3 Ruddlesden - Popper compound

Journal of Physics: Condensed Matter, 1998

... AI Mihut†, LE Spring†, RI Bewley†, SJ Blundell†, W Hayes†, Th Jestädt†, BW Lovett†, R McDonal... more ... AI Mihut†, LE Spring†, RI Bewley†, SJ Blundell†, W Hayes†, Th Jestädt†, BW Lovett†, R McDonald†, FL Pratt†, J Singleton†, PD Battle‡, J ... proportional to the square of the magnetization, and is largest at low temperatures; a 40% drop in resistivity is observed in a magnetic field ...

Research paper thumbnail of Magnetization and spin dynamics of a Cr-based magnetic cluster

Journal of Magnetism and Magnetic Materials, 2010

We study the magnetization and the spin dynamics of the Cr7Ni ring-shaped magnetic cluster. Measu... more We study the magnetization and the spin dynamics of the Cr7Ni ring-shaped magnetic cluster. Measurements of the magnetization at high pulsed fields and low temperature are compared to calculations and show that the spin Hamiltonian approach provides a good description of Cr7Ni magnetic molecule. In addition, the phonon-induced relaxation dynamics of molecular observables has been investigated. By assuming the spin-phonon coupling to take place through the modulation of the local crystal fields, it is possible to evaluate the decay of fluctuations of two generic molecular observables. The nuclear spin-lattice relaxation rate 1/T1 directly probes such fluctuations, and allows to determine the magnetoelastic coupling strength.

Research paper thumbnail of Evaluation of a methylation procedure to determine cyclopropenoids fatty acids from Sterculia striata St. Hil. Et Nauds seed oil

Journal of Chromatography A, 2004

Cyclopropenoids fatty acids (CPFA) from Sterculia striata seed oil were characterized by gas chro... more Cyclopropenoids fatty acids (CPFA) from Sterculia striata seed oil were characterized by gas chromatography/mass spectrometry (GC/MS) and quantified by gas chromatography-flame ionization detector (GC-FID) after derivation to fatty acid methyl esters using a cold basecatalyzed procedure. 1 H nuclear magnetic resonance (NMR) analysis were done in oil and fatty acid methyl esters derivatives to quantify CPFA and verify artifacts formation during the base-catalyzed reaction. Similar quantities of CPFA were found in S. striata and Sterculia foetida seed oils before and after a base-catalyzed methylation by NMR analysis, with no artifact formation. These results were compatible with those obtained by GC-FID analysis. Transmethylation with KOH in methanol was an appropriated method to prepare cyclopropenoids fatty acids methyl esters and quantify them by GC and NMR analysis.

Research paper thumbnail of Local spin dynamics in magnetic molecular chains studied by NMR and μSR

Inorganica Chimica Acta, 2007

We present NMR and l + SR study of spin dynamics in one-dimensional and quasi-one-dimensional mol... more We present NMR and l + SR study of spin dynamics in one-dimensional and quasi-one-dimensional molecular magnets of recent synthesis. In particular, we focus on the so called Gd(hfac) 3 NIT-R and CoPhOMe magnetic chains families. For Gd-R helimagnets we show some differences between ''weakly frustrated systems'' and ''fully frustrated systems''. The different behaviour is due to the different radical inserted in the chains (R = Me, Ph for ''weakly frustrated systems'' and R = iPr, Et for ''fully frustrated systems''). The existence of different phase transitions, particularly to 3D long-range magnetic order in Gd-Ph and to chiral order in Gd-iPr, is remarked together with a comparison between results obtained from macroscopic and microscopic investigating techniques. As regards CoPhOMe slowly relaxing chain, the 1 H NMR measurements confirm the freezing of the spins at low temperature, which prevents the 3D long-range order, and display the presence of two relaxation mechanisms related to distinct contributions to the local spin relaxation.

Research paper thumbnail of 19F nuclear spin relaxation and spin diffusion effects in the single-ion magnet LiYF4:Ho3+

The European Physical Journal B, 2008

Temperature and magnetic field dependences of the 19 F nuclear spin-lattice relaxation in a singl... more Temperature and magnetic field dependences of the 19 F nuclear spin-lattice relaxation in a single crystal of LiYF 4 doped with holmium are described by an approach based on a detailed consideration of the magnetic dipole-dipole interactions between nuclei and impurity paramagnetic ions and nuclear spin diffusion processes. The observed nonexponential long time recovery of the nuclear magnetization after saturation at intermediate temperatures is in agreement with predictions of the spin-diffusion theory in a case of the diffusion limited relaxation. At avoided level crossings in the spectrum of electron-nuclear states of Ho 3+ ions, rates of nuclear spin-lattice relaxation increase due to quasi-resonant energy exchange between nuclei and paramagnetic ions in contrast to the predominant role played by electronic cross-relaxation processes in the low-frequency ac-susceptibility. PACS. 76.60.-k Nuclear magnetic resonance and relaxation -75.40.Gb Dynamic properties -76.30.Kg Magnetic resonances and relaxations in condensed matter Rare-earth ions and impurities __________________________________________ a

Research paper thumbnail of Sesquiterpenes, diterpenes, steroids and alkaloid from branches of Xylopia brasiliensis Spreng (Annonaceae)

Biochemical Systematics and Ecology, 2005

RefDoc Bienvenue - Welcome. Refdoc est un service / is powered by. ...

Research paper thumbnail of μSR investigation of spin dynamics in pure and Zn-doped Co (hfac) 2NITPhOMe single-chain magnet

Research paper thumbnail of Low-energy spin dynamics in the giant keplerate molecule {Mo72Fe30}: A muon spin relaxation and H1 NMR investigation

Physical Review B, 2007

We present muon spin relaxation and H1 NMR results on the magnetically frustrated keplerate molec... more We present muon spin relaxation and H1 NMR results on the magnetically frustrated keplerate molecule {Mo72Fe30} , aimed at studying the local spin dynamics as a function of temperature. We find that, in common with other molecular magnets, the relaxation spectrum of this material is characterized by a single dominating electronic correlation time tau . Experiments and theory show that tau has a thermally activated behavior with an activation gap of the order of the energy difference between the lowest-lying rotational bands in this material. This shows that, in the intermediate temperature range just above 1K , the relaxation of the electronic spin system occurs via Orbach processes involving energy levels belonging to the two lowest-lying rotational bands. Our data thus provide an experimental estimate of the first interband gap.

Research paper thumbnail of Phonon-induced relaxation in the Cr_{7}Ni magnetic molecule probed by NMR

Physical Review B, 2010

We study the phonon-induced relaxation dynamics in the heterometallic Cr7Ni ring. By assuming tha... more We study the phonon-induced relaxation dynamics in the heterometallic Cr7Ni ring. By assuming that spin-phonon coupling occurs through the modulation of local crystal fields, we investigate the decay of time correlations of molecular observables, such as fluctuations of the cluster magnetization. Single-crystal H1 nuclear magnetic resonance measurements have been performed for two orthogonal orientations of the applied magnetic field. The

Research paper thumbnail of Glassy dynamics in the low-temperature inhomogeneous ferromagnetic phase of the quantum spin ice Yb<span class="aps-inline-formula"><math><msub><mrow></mrow><mn>2</mn></msub></math></span>Sn<span class="aps-inline-formula"><math><msub><mrow></mrow><mn>2</mn></msub></math></span>O<span class="aps-...

Physical Review B, 2014

Here we present a detailed muon spin relaxation (μSR), neutron diffraction, and ac-susceptibility... more Here we present a detailed muon spin relaxation (μSR), neutron diffraction, and ac-susceptibility study of Yb 2 Sn 2 O 7 that shows that despite the onset of ferromagnetic long-range order at T c ≈ 0.140 K, the lowtemperature phase of this material remains highly disordered with glassy dynamics that span various frequency decades. We suggest that the observed disordered ground state might be made of infinite, percolating clusters coexisting with smaller ones. This mesoscopic cluster glass state would be the result of the enhanced effect of even a small amount of disorder, capable of disrupting the "clean" ordered state near a quantum critical point.