Critical behavior of the ferromagnetic metal La₃CrAs₅ with quasi-one-dimensional spin chains

In this work, we report on the critical properties of ferromagnetic metal La₃CrAs₅, where the face-sharing CrAs₆ octahedral chains are separated by a large distance. Bulk magnetization measurements near the Curie temperature T_C are carried out in details. Then we used modified Arrott plot, Kouvel-Fisher method and critical isotherm analysis to analyze the isothermal magnetization curves, and thus obtained a set of precise and self-consistent critical exponents (β, γ and δ), which are close to the theoretical values of chiral XY model. In addition, the scaling equation is followed by the magnetization-field-temperature curves, confirming the reliability of these critical exponents. Furthermore, the magnetic exchange distance, decaying as J(r) ~ r^−4.7, indicates the predominant long-range magnetic coupling in La₃CrAs₅. Furthermore, the magnetic entropy change − ΔS_M around the T_C reaches a maximum value, such as−ΔS_M^max is 1.23 J/kg-K for H = 50 kOe, and the relative cooling power (RCP) is 51.70 J/kg at H = 50 kOe. Our results reveal that the magnetic critical behavior in La₃CrAs₅ should be attributed to the synergistic action between the direct magnetic exchange and the itinerant electron mediated indirect spin exchange, and the interchain spin coupling should be greatly enhanced via the itinerant electrons and then leads to the increase of the long-range magnetic ordering temperature.