Tunable Magnetic Chromism on Copper Molybdate

本文报道了用零场比热测量方法，在1.75K首次观察到铬化合物CuMoO_4的长角磁序。在4.2K下进行的高达57T的磁化强度测量表明，在饱和磁化强度的1/3处有一个平台，这符合两个不相互作用的Cu^&lt；2+&gt；自旋和两个孤立的反铁磁二聚体(J/k_B=26K)的简单磁模型。磁化率有较大的温滞效应源于结构相变，并与α-CuMo0_4(绿色)和γ-CuMo0-4(棕红)之间的色度密切相关。在很宽的温度范围内，CuL_xZn，Mo04(0≦x≦0.1)和CuMo_&lt；1-y&gt；W_y，0_4(0&lt；y&lt；0.1)中的替代效应可以调节这种不连续的相变。

We report the first observation of long-ange magnetic order in the chromic compound CuMo0_4 at 1. 75K by means of a specific heat measurement in zero magnetic field. Magnetization measurements performed up to 57T at 4. 2K indicate a plateau at 1/3 of the saturated magnetization consistent with a simple magnetic model of two non-nteracting Cu^<2+> spins and two isolated antiferromagnetic dimers(J/k_B=26K). A large temperature-ysteresis in the magnetic susceptibility is observed to originate from the structural phase transition and to be closely related to chromism between α-CuMo0_4(green) and γ-CuMo0-4(brownish-red). This discontinuous phase transition is tunable using substitutional effects in Cul_XZn, Mo04(0≦x≦0.1} and CuMo_<1-y>W_y,0_4(0<y<0.1) over a wide range of temperatures.