Magnetic and Thermodynamic Properties of FeCr2Se4

Abstract

Magnetic and thermodynamic properties of a selenide FeCr2Se4 have been investigated. Electric resistivity ρ(T) shows insulator-type temperature dependence defined as ∂ρ(T)/∂T < 0 in the range 2.5 <T < 300 K At TN ∼ 200 K, ρ(T) has an inflection point associated with antiferromagnetic order. A cusp-like anomaly appears at TN in temperature dependence of dc-magnetic susceptibility χ(T). An effective magnetic moment μeff = 7.66 is obtained from Curie constant C and this value is close to the one (μeff = 7.35) calculated from coupling of the Curie constant for Fe2+ (spin angular momentum S = 2) and Cr3+ (S = 3/2). At T = 75 K, χ(T) increases abruptly with decreasing T. Below 20 K, between the values χ(T) of zero-field-cooled (ZFC) and field-cooled (FC) show the irreversibility, and χ(T) of ZFC has a broad peak at 5 K On the other hand, in the T dependence of specific heat CP(T) in the range 1.5K < T < TN, although λ-type anomaly appears at TN, an anomaly which indicates the additional magnetic phase transition is not observed.