  Understanding spin control mechanisms is an important part of condensed
matter physics and the theoretical basis for designing spintronic devices. In
this letter, based on four-sublattices molecular field theory, we propose that
the underlying NdFe1-xCrxO3 magnetic mechanism is driven by spin reorientation
sensitive to temperature. The actual coupling angular momentum, angle between
the Nd3+ and Cr3+/Fe3+ moments at the given temperature is realized via the
Nd3+ magnetic moment projection onto the Cr3+/Fe3+ plane. As the temperature
increases, the angle between the moment of Nd3+ and the moment of Cr3+/Fe3+
decreases monotonically. In this work, the magnetic mechanism of NdFe1-xCrxO3
(x=0.1, 0.9), the close relationship between A/B angle and temperature are
presented, which laid a theoretical foundation for the design of new
multifunctional magnetic materials.
