Temperature evolution of the effective magnetic anisotropy in the MnCr₂O₄spinel

Abstract

In this work we present a study of the low temperature magnetic phases of polycrystalline MnCr 2 O 4 spinel through dc magnetization and ferromagnetic resonance spectroscopy (FMR). Through these experiments we determined the main characteristic temperatures: T C 41 K and T H~ 18 K corresponding, respectively, to the ferrimagnetic order and to the low temperature helicoidal transitions. The temperature evolution of the system is described by a phenomenological approach that considers the different terms that contribute to the free energy density. Below the Curie temperature the FMR spectra were modeled by a cubic magnetocrystalline anisotropy to the second order, with K 1 and K 2 anisotropy constants that define the easy magnetization axis along the <110> direction. At lower temperatures, the formation of a helicoidal phase was considered by including uniaxial anisotropy axis along

Model for the field cooled and zero field cooled ferrimagnetic spinel

“…This is because at zero temperature the Bose functions of α k and β k excitations, in equations (13), are equal to zero, therefore, at zero temperature…”

“…This explains the decreasing of the partial order critical temperature T * when the applied, under preparation, magnetic field increases. The Néel temperature is determined by the gapless α and gapped β excitations (13). They are complicate mixture of the transversal fluctuations of A and B spins (6), which have gapped dispersions: ε a k=0 = 8Jus B μ A , ε b k=0 = 8Jus A μ B .…”

“…The magnetization-temperature and magnetic susceptibility curves for zero field cooled (ZFC) and non-zero field cooled (FC) ferrimagnetic spinel display a notable difference below Néel T N temperature [1]- [13]. The (ZFC) curve exhibits a maximum and then a monotonic decrease upon cooling from T N , while the (FC) curve increases steeply, shows a dip near the temperature at which the (ZFC) curve has a maximum and finally increases monotonically.…”

Effect of Al substitution on the magnetization reversal and complex magnetic properties of NiCr2O4 ceramics

“…With the field increasing continuously, the angles between the normal and inverse magnetic moments can be changed by a torque obtained from the applied field as reported in the MnCr 2 O 4 system. 24 And thus the inverse moment is canted, leading to the net magnetization decrease to attain a positive value. Fig.…”

Sequence of superconducting states in field cooled $FeCr_2S_4$

“…If the applied field is below 0.01T it is zero field cooled (ZFC). The magnetization-temperature and magnetic susceptibility curves for (ZFC) and (FC) spinel show a remarkable difference below Néel T N temperature [36][37][38][39][40][41][42][43][44][45][46][47][48] . In the case of F eCr 2 S 4 spinel the curves, which show the temperature dependence of spontaneous magnetization M s , are depicted in Fig.…”