A study of the magnetization of the antiferromagnetic magnetoelectric crystal LiCoPO4 as a function of temperature and the strength of a magnetic field oriented along the antiferromagnetic vector reveals features due to the presence of a weak ferromagnetic moment. The value of the magnetic moment along the b axis at 15 K is approximately 0.12 G. The existence of a ferromagnetic moment can account for the anomalous behavior of the magnetoelectric effect observed previously in this crystal.

Articles you may be interested inSpin reorientation transition and near room-temperature multiferroic properties in a W-type hexaferrite SrZn1.15Co0.85Fe16O27It has been found experimentally that in the strongly anisotropic orthorhombic antiferromagnetic crystal LiCoPO 4 ͑T N = 21.7 K͒ the destruction of antiferromagnetic order by a magnetic field directed along the antiferromagnetism axis H ʈ b occurs in steps by means of three phase transitions: two first-order transitions in the fields H 1 = 118 kOe, H 2 = 224 Oe and one second-order phase transition in the field H 3 = 283 kOe ͑T = 1.7 K͒. A section of magnetic fields ͑H 2 , H 3 ͒ where the magnetization of the crystal varies almost linearly with the field was found. Possible magnetic structures formed in a magnetic field are discussed. The values of the exchange parameters are estimated.

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