Magnetic, magnetothermal, and magnetotransport properties in SmMn2Si2−xGex compounds

Abstract

Magnetic properties of isotropic Sm-Fe-N magnets produced by compression shearing method J. Appl. Phys. 111, 07A716 (2012) Stable vortex magnetite nanorings colloid: Micromagnetic simulation and experimental demonstration J. Appl. Phys. 111, 044303 (2012) Evidence for low temperature glassy behavior in La0.5Sr0.5CoO3 J. Appl. Phys. 111, 043902 (2012) Temperature dependent phonon Raman scattering of highly a-axis oriented CoFe2O4 inverse spinel ferromagnetic films grown by pulsed laser deposition Appl. Phys. Lett. 100, 071905 (2012) Additional information on J. Appl. Phys. The effect of Ge substitution for Si in SmMn 2 Si 2−x Ge x compounds has been studied. The Sm ordering temperature is found to be much larger in the compound with x = 2, as compared to the compounds with x = 0 and 1. The increase in the intralayer Mn-Mn distance is attributed to this variation. Among these three compounds, SmMn 2 Ge 2 is found to show reentrant ferromagnetism at low temperatures. The magnetic contribution to the heat capacity has been calculated in all the three compounds. The splitting of the ground state multiplet has been estimated by fitting the magnetic part of the heat capacity data, using the Schottky formula. The isothermal magnetic entropy change is found to remain the same for x = 0 and 1 but decreases in the compound with x = 2, though the nature of magnetic transition changes from second order to first order, as x is increased from 0 to 2. The electrical resistivity increases with Ge concentration. The excess resistivity in the antiferromagnetic region has been calculated.

Pressure-induced changes in the magnetic and magnetocaloric properties ofRMn2Ge2(RKumar1, Суреш2, Nigam3 et al. 2008Phys. Rev. BSelf Cite462260View full textAdd to dashboardCite

“…Recently we have reported 19 the effect of chemical pressure brought about by Si substitution for Ge in SmMn 2 Ge 2 . It was found that the transition temperature T 1 decreases from 110 to 39 K, as Ge is completely replaced with Si.…”

“…The magnetocaloric effect has been calculated in terms of isothermal magnetic entropy change ͑⌬S M ͒ using the methods described elsewhere, 18,19 employing the magnetization isotherms obtained near the transition temperatures. Figure 5 shows the variation of magnetic entropy change in SmMn 2 Ge 2 for a field change of 50 kOe under different pressures.…”

“…18,19 The magnetization ͑M͒ measurements under various applied pressures ͑P͒ have been performed using in a superconducting quantum interference device ͑SQUID͒ magnetometer ͑Quantum Design͒ attached with a Cu-Be clamp type pressure cell ͑maximum pressure ϳ12 kbar͒. The magnetic transition temperatures have been calculated from the ͑dM / dT͒ plots obtained from the ZFC M-T data.…”

Tuning the magnetic and structural transitions in TbCo2Mnx compounds

“…An obvious peak appears at 284 K which is ascribed to the ferromagnetic transition of TbCo 2 Mn 0.1 . The total heat capacity C(T) of a metallic magnetic material can be described as the sum of various contributions from phonons, electrons, and magnon [23]:…”

The influence of substitution of Mn by Fe and Co on magnetocaloric effect and magnetoresistance properties of SmMn2Ge2

“…8(a and b), the resistivity in the antiferromagnetic state is higher than that in the ferromagnetic state. The higher resistivity in the antiferromagnetic state than in the ferromagnetic state is in good agreement with the behavior of polycrystalline La 0.15 Gd 0.85 Mn 2 Ge 2 , Gd 0.925 La 0.0725 Mn 2 Ge 2 , SmMn 2 Ge 2 and Sm 0.9 Y 0.1 Mn 2 Ge 2 [16,[22][23][24]. MR is generally defined by…”