Magneto-History Effect in the TbxGd1-xNi3 Compounds

The compounds TbxGd1-xNi3 with a PuNi3-type structure have been obtained. The magnetic properties have been investigated by using SQUID magnetometer (Quantum Design MPMS, temperature from 1.9 K to 300 K and magnetic field up to 7 T). The partial replacement of Gd by Tb atoms is reflected in a decrease of the ordering temperature from 115 K (x = 0.0) to 81 K (x = 1.0) as well as the increase of the saturation magnetic moment M-S from 6.93 mu(B)/f.u. (x = 0:0) to 7.14 mu(B)/f.u. (x = 1.0). A large difference of M(T) curves has been noticed between the so-called field cooling-zero field cooling magnetization. The thermomagnetic curves are sensitive to the applied magnetic field and their origin can be understood as the domain-wall pinning effect and as the temperature dependence of coercivity.