Magnetic Phase Diagram of (Ni1−xMgx)O Solid Solutions

Abstract
A magnetic phase diagram of the (Ni1−xMgx)O solid solutions is drawn by the results of elastic magnetic neutron scattering and magnetic measurements. The ranges of homogeneous antiferromagnetism (0 ≦ x ≦0.37), tricritical behaviour or frustrated antiferromagnetism (0.37 < x ≦ 0.6), cluster spin glass (0.6 < x ≦ 0.75) and paramagnetic behaviour of the Ni2+ spin moments in the ground state (x ≧ 0.8) are determined. It is shown that diamagnetic Mg2+ ions serve as a source of a random field inducing an extra diamagnetic moment of value 0.35μB.