Magnetism of Mg1-x Mnx O4 spinels by SQUID magnetometry and muon spin rotation spectroscopy

The magnetic properties of the substituted spinel Mg1-x Mnx Mn2 O4, with 0≤x≤1, were investigated by means of superconducting quantum interference device (SQUID) magnetometry and μSR spectroscopy. A zero-field muon spin precession is detected in the two end members and the appearance of static internal fields is evidenced in all samples below a weakly x -dependent ordering temperature TN, different from that detected by macroscopic magnetization, TM. For x close to 1 a noncollinear spin structure as in Mn3 O4 is compatible with our low temperature results. At the opposite end (x close to zero) SQUID and μSR data suggest an antiferromagnetic arrangement of the Mn ions on the B spinel site. A nontrivial finding is that the uniform (q=0) component of the magnetic moment scales linearly with x. This evidence is discussed on the basis of the known magnetic structure of Mn3 O