Phước Cao Văn - Academia.edu (original) (raw)

Papers by Phước Cao Văn

Current Applied Physics, Feb 1, 2018

This work investigated the effects of heating rate and annealing on the magneto-optical propertie... more This work investigated the effects of heating rate and annealing on the magneto-optical properties of bismuth-substituted yttrium iron garnet (Bi-YIG) thin films on glass and ( )-oriented single-crystalline gadolinium gallium garnet (GGG) substrates fabricated by metal-organic decomposition (MOD). We modified the MOD method by eliminating the pre-annealing process. We performed annealing at various temperatures to determine the optimal temperature for obtaining the Bi-YIG phase. We then annealed at the optimized temperature using various heating rates. The optimal conditions were annealing for 1 h at 750 C at a heating rate of 30 C/min on GGG to obtain highly crystallized fine grains. The Faraday rotation for this film was about À10.5 /mm. The optimized heating rate enhanced the magneto-optical properties due to improved crystallinity and saturated magnetization. The Bi-YIG thin films prepared by this prescribed MOD method exhibited excellent magneto-optical performance and are potential candidates for applications in optical devices.

Korean Journal of Materials Research, Dec 1, 2015

Journal of environmental chemical engineering, Dec 1, 2021

Journal of Alloys and Compounds, 2021

RSC Advances, 2018

Abnormal levels of dopamine (DA) in body fluids is an indication of serious health issues, hence ... more Abnormal levels of dopamine (DA) in body fluids is an indication of serious health issues, hence development of highly sensitive platforms for the precise detection of DA is highly essential.

RSC Advances, 2020

Controlling impedance matching and enhancing absorption properties are crucial for developing nex... more Controlling impedance matching and enhancing absorption properties are crucial for developing next-generation microwave absorbing materials.

Nature Communications, Jun 8, 2023

Magnetochemistry, Feb 27, 2022

This article is an open access article distributed under the terms and conditions of the Creative... more This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY

Physical review, Jan 14, 2021

We investigate the magnetoresistance of ferrimagnetic GdFeCo across the magnetization compensatio... more We investigate the magnetoresistance of ferrimagnetic GdFeCo across the magnetization compensation temperature T M. The magnetic field dependence of longitudinal resistivity (ρ xx) shows opposite trends below and above T M , and the variation of ρ xx with B becomes more significant as the temperature decreases. The observed unconventional magnetoresistance is attributed to the sperimagnetism of GdFeCo. Further investigations on the transverse resistivity (ρ xy) of GdFeCo unveils that, contrary to the recent reports that the transition metal dominates transport of rare-earth transition-metal ferrimagnets, the Gd contribution to magnetoresistance is comparable to the FeCo contribution, showing that the transport of GdFeCo is antiferromagnetic. Our results therefore show that ferrimagnets are a convenient platform for studying antiferromagnetic spin transport and also are potential materials that can enable antiferromagnetic spin devices.

Thin Solid Films, Jun 1, 2023

Nano Letters, Oct 15, 2020

Coupling of spin and heat currents enables the spin Nernst effect, the thermal generation of spin... more Coupling of spin and heat currents enables the spin Nernst effect, the thermal generation of spin currents in nonmagnets that have strong spin-orbit interaction. Analogous to the spin Hall effect that electrically generates spin currents and associated electrical spin-orbit torques (SOTs), the spin Nernst effect can exert thermal SOTs on an adjacent magnetic layer and control the magnetization direction. Here, the thermal SOT caused by the spin Nernst effect is experimentally demonstrated in W/CoFeB/MgO structures. It is found that an in-plane temperature gradient across the sample generates a magnetic torque and modulates the switching field of the perpendicularly magnetized CoFeB. The W thickness dependence suggests that the torque originates mainly from thermal spin currents induced in W. Moreover, the thermal SOT reduces the critical current for SOT-induced magnetization switching, demonstrating that it can be utilized to control the magnetization in spintronic devices.

Applied Physics Letters, Oct 11, 2021

The non-equilibrium state between magnons and phonons is the key to understand the spin-caloric p... more The non-equilibrium state between magnons and phonons is the key to understand the spin-caloric phenomena. We developed a unique optical reflectometry technique to spatially resolve Kerr angle (θK) and optical reflectance (R) in a magnetic insulator—thulium iron garnet (TmIG). The TmIG was subjected to a thermal gradient to estimate populations of thermally excited magnons and phonons through the variation of θK and R. The results showed that the spatial gradient of θK is different from that of R, indicating the non-equilibrium state between magnons and phonons. Particularly, the characteristic decay length of θK was significantly influenced by the heating power and the magnetic field, suggesting non-linear magnon scattering in a high magnon density regime. Our work not only provides a scheme to investigate the spatial profiles of magnons and phonons but also reveals the magnon–phonon non-equilibrium in TmIG. Hence, this report will stimulate further studies based on magnon–phonon non-equilibrium such as a transverse spin Seebeck effect and Bose–Einstein condensation.

Research Square (Research Square), Aug 13, 2021

The quasi-static strain (QSS) is the product generated by the lattice thermal expansion after ult... more The quasi-static strain (QSS) is the product generated by the lattice thermal expansion after ultrafast photo-excitation and the effects of thermal and QSS are inextricable. Nevertheless, the two phenomena with the same relaxation timescale should be treated separately because of their different fundamental actions to the ultrafast spin dynamics. By employing ultrafast Sagnac interferometry and magneto-optical Kerr effect, we quantitatively prove the existence of QSS, which has been disregarded, and decouple two effects counteracting each other. Through the magnetoelastic energy analysis, rather we show that QSS in ferromagnets plays a governing role on ultrafast spin dynamics, which is opposite to what have been known on the basis of thermal effect. Our demonstration provides an essential way of analysis on ultrafast photo-induced phenomena.

Journal of Magnetics, Mar 31, 2022

In this study, spin Seebeck effect (SSE) signals caused by a thermal gradient induced by Joule an... more In this study, spin Seebeck effect (SSE) signals caused by a thermal gradient induced by Joule and laser heating were examined. A Pt/Y 3 Fe 5 O 12 /Gd 3 Ga 5 O 12 sample was used as the reference for SSE measurement. Both the Joule heating-and laser heating-based SSE measurement systems captured SSE hysteresis loops consistent with the magnetic hysteresis loop of the sample. The laser heating-based system measured a higher SSE signal; however, heat flux could not be precisely evaluated. With the Joule heating-based system, the spin Seebeck resistivity (SSR) was 21.2 ± 1 nm/A, comparable with the values obtained in other studies and indicating the feasibility of our apparatus for investigating SSE.

Journal of Magnetics

Praseodymium (Pr)-and bismuth (Bi)-substituted yttrium (Y) iron (Fe) garnet (Pr x Y 2-x Bi 1 Fe 5... more Praseodymium (Pr)-and bismuth (Bi)-substituted yttrium (Y) iron (Fe) garnet (Pr x Y 2-x Bi 1 Fe 5 O 12 where x = 0.25, 0.5, 1, and 2) thin films were prepared on glass substrate using a metal-organic decomposition (MOD) method. Their magneto-optical properties were studied as a function of Pr concentration. Praseodymium has two functions in Pr x Y 2-x Bi 1 Fe 5 O 12 thin films, i.e., it (i) improves spin-orbit interaction strength and (ii) increases magnetic properties; both are expected to strongly enhance the Faraday rotation (FR) angle of the thin film. Our study demonstrated that the Pr 1 Y 1 Bi 1 Fe 5 O 12 thin-film displayed the highest FR angle, of-13 °/μm, which is 1.6-times higher than that of the Pr x Y 2-x Bi 1 Fe 5 O 12 thin film without Pr dopant. The Pr 1 Bi 1 Y 1 Fe 5 O 12 thin film fabricated on a glass substrate by the MOD method displayed excellent MO performance and is a potential candidate for application in optical devices.

Journal of Alloys and Compounds

Sensors and Actuators A: Physical