
%0 Journal Article
%A Muroi, Michihito 
%A Street, Robert 
%T Evolution of Ferromagnetism in LaMnO<emph tye="8">3+&#948;</emph>
%J Australian Journal of Physics
%D 1999/04/28
%V 52
%N 2
%P 205-225
%K 
%R https://doi.org/10.1071/P98059
%U https://www.publish.csiro.au/paper/P98059 
%X An extensive study has been made of the magnetic properties of LaMnO3+&#948; with finely tuned hole concentrations, x (=2&#948;), ranging between 0&#183;08 and 0&#183;15. As x increases in the range studied, the spontaneous magnetisation at low temperature increases from only about 20% to almost 100% of the value for full polarisation of Mn spins, and the coercivity Hc decreases by more than an order of magnitude, e.g. from 4&#183;2 kOe to 120 Oe at 5 K. The magnetic ordering temperature Tc takes a minimum at x = xc ~ 0&#183;12. For x &#60; xc, the inverse susceptibility shows a marked decrease as Tc is approached from above. Measurements of minor hysteresis loops for the sample with x = 0&#183;08 show that magnetisation is reversible with respect to field changes except near Hc. These observations are discussed in terms of a two-phase exchange coupling (TPEC) model in which it is assumed that at low temperature the system separates into two phases, a hole-free antiferromagnetic phase and an optimally doped ferromagnetic phase, and the two phases are coupled through superexchange interactions at the interface. 
