title: Temperature evolution of the effective magnetic anisotropy in the MnCr₂O₄ spinel.
abstract: In this work, we present a study of the low temperature magnetic phases of polycrystalline MnCr2O4 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 K1 and K2 anisotropy constants that define the easy magnetization axis along the <1 1 0> direction. At lower temperatures, the formation of a helicoidal phase was considered by including uniaxial anisotropy axis along the [11¯0] propagation direction of the spiral arrange, with a Ku anisotropy constant. The values obtained from the fittings at 5 K are K1 = -2.3 × 10(4) erg cm(-3), K2 = 6.4 × 10(4) erg cm(-3) and Ku = 7.5 × 10(4) erg cm(-3).
authors.affiliation: Centro Atómico Bariloche, CNEA, 8400 S.C. de Bariloche, Río Negro, Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Argentina.
authors.forename: Dina
authors.initials: D
authors.lastname: Tobia
authors.forename: Julián
authors.initials: J
authors.lastname: Milano
authors.forename: María Teresa
authors.initials: MT
authors.lastname: Causa
authors.forename: Elin L
authors.initials: EL
authors.lastname: Winkler