6 research outputs found
Evolution Of The Magnetic Properties On Van Der Waals Layered Magnets Via Pressure And Proton Irradiation
No full textProbing the magnetism in quasi two-dimensional materials has the potential in driving their properties towards future use in spin electronic based devices. Studying such layered magnets will enable the scientific community to uncover tunable exotic phases such as superconductivity, quantum paramagnetism, etc. This work examines the influence of two types of external perturbations, namely, the pressure and proton irradiation, on the magnetic properties of several compounds in the van der Waals crystal family.
Pressure has been found to induce structural and magnetic phase transitions in many of these materials. Using hydrostatic pressure as a disorderless approach to manipulate the interlayer coupling, we apply pressure to CrBr3, Fe2.7GeTe2, Mn3Si2Te6, and CrSiTe3 with a high-pressure piston cell up to ~1.3 GPa. Materials with weakly held layers allow relatively easy manipulation of the superexchange mechanism. Magnetic property measurements revealed that each material studied has shown the ability to have their corresponding Curie temperature (TC) and the saturation magnetization tuned by pressure. The overall pressure effect on layer separation, bond angle, and exchange coupling are found to strongly influence the change in subsequent magnetic characteristics.
Proton irradiation was employed to manipulate the spin fluctuations on Mn3Si2Te6 (MST) and being irradiated at 1 Ã 1015, 5 Ã 1015,1 Ã 1016, and 1 Ã 1018 H+/cm2. A critical behavior analysis was performed to examine the physical system at the critical point for each fluence rate. The analytical study of the critical phenomena has been used to discern the magnetic behavior of proton irradiated MST. In this work, we report the critical parameters related to magnetization, magnetic susceptibility, exchange distance, space and spin dimensionality to sort the universality class as a function of proton irradiance
Pressure dependent magnetic properties on bulk CrBr3 single crystals
No full textThe van der Waals class of materials offer an approach to two-dimensional magnetism as their spin fluctuations can be tuned upon exfoliation of layers. Moreover, it has recently been shown that spin-lattice coupling and long-range magnetic ordering can be modified with pressure in van der Waals materials. In this work, the magnetic properties of quasi two-dimensional CrBr3 are reported applying hydrostatic pressure. The application of pressure up to 0.844 GPa shows a 1.77% decrease in saturation magnetization with a decrease in the Curie temperature from 33.05 to 30.41 K. Density functional theory calculations with pressure up to 1 GPa show a reduction in volume and interplanar distance as pressure increases. To further understand the magnetic properties with applied pressure, the magnetocrystalline anisotropy energy (MAE) and exchange coupling parameter(s) (J) are calculated. There is small decrease in MAE and the first nearest neighbor interaction (J1) (U = 2.7 eV and J = 0.7 eV) is increasing with respect to increasing pressure. Overall, CrBr3 displays ferromagnetic interlayer coupling and the calculated exchange coupling and MAE parameters match well with the observations from the experimental work.This is a manuscript of an article published as Olmos, Rubyann, Shamsul Alam, Po-Hao Chang, Kinjal Gandha, Ikenna C. Nlebedim, Andrew Cole, Fazel Tafti, Rajendra R. Zope, and Srinivasa R. Singamaneni. "Pressure dependent magnetic properties on bulk CrBr3 single crystals." Journal of Alloys and Compounds 911 (2022): 165034.
DOI: 10.1016/j.jallcom.2022.165034.
Copyright 2022 Elsevier B.V.
Posted with permission.
DOE Contract Number(s): AC02-07CH11358
Exchange bias in La0.7Sr0.3CrO3/La0.7Sr0.3MnO3/La0.7Sr0.3CrO3 heterostructures
No full textIn the recent past, heterostructures of magnetic oxide thin films have attracted a great deal of research excitement due to very interesting physical properties such as antiferromagnetic interlayer coupling, tunable exchange-bias, interfacial driven magnetic properties and high mobility electron gas across the interfaces. In this work, we report on the comprehensive magnetic properties observed from the heterostructures of (2 unit cells) La0.7Sr0.3CrO3/(8 unit cells) La0.7Sr0.3MnO3/(2 unit cells) La0.7Sr0.3CrO3, which are epitaxially deposited on SrTiO3 substrate by plasma-assisted oxide molecular beam epitaxy. Using SQUID magnetometer, the magnetic properties are studied when the magnetic field was applied both in plane and out of plane. The Curie temperature of this structure is found to be at 290 K. Most significantly, at 2 K, we observed a complete up/down shift (along magnetization axis) of hysteresis loop when the sample was cooled under a magnetic field of ± 5000 Oe in the in-plane configuration. We believe that the strong antiferromagnetic (super) exchange coupling of Mn-Cr across the two interfaces is responsible for the observed exchange bias. We will present and discuss our in-detailed experimental findings collected on this heterostructure as a function of temperature and magnetic field.</p
Pressure-Dependent Magnetic Properties of Quasi-2D Cr<sub>2</sub>Si<sub>2</sub>Te<sub>6</sub> and Mn<sub>3</sub>Si<sub>2</sub>Te<sub>6</sub>
No full textRecently, pressure has been used to induce structural
and magnetic
phase transitions in many layered quantum materials whose layers are
linked by van der Waals forces. Materials with such weakly held layers
allow for relatively easy manipulation of the superexchange mechanism,
which can give rise to novel magnetic behavior. Using hydrostatic
pressure as a disorderless means to manipulate the interlayer coupling,
we applied pressure on two quasi-2D sister compounds, namely, Cr2Si2Te6 (CST) and Mn3Si2Te6 (MST), up to ∼1 GPa. Magnetic property
measurements with the application of pressure revealed that the ferromagnetic
transition temperature decreases in CST, while the opposite occurs
for the ferrimagnetic MST. In MST, magnetization decreases with the
increase in pressure, and such a trend is not clearly observed within
the pressure range studied for CST. The overall pressure effect on
magnetic characteristics such as exchange couplings and magnetic anisotropy
energies is also examined theoretically using density functional theory.
Exchange coupling in MST is strongly frustrated, and the first nearest
neighbor interaction is the most dominant of the components with the
strongest pressure dependence. In CST, the exchange coupling parameters
exhibit very little dependence on pressure. This combined experimental
and theoretical work has the potential to expand to other relevant
quantum materials
