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Complex studies of the magnetic, magnetoelectric, and magnetoelastic properties of GdMn2O5 single crystals in strong pulsed magnetic fields are carried out in order to obtain additional indirect information on the character of the rare-earth and manganese spin ordering. It is shown that magnetic ordering of Gd3+ spins affects the manganese sublattice spin orientation and initiates new magnetic phase transitions. The observed magnetoelectric properties of the GdMn2O5 system are interpreted in terms of the theory of phase transitions.

This paper reports on the results of investigations into the magnetic and magnetoelastic properties of Nd0.5Sr0.5MnO3 single crystals in pulsed magnetic fields up to 250 kOe, the magnetic and kinetic properties of these crystals in weak static magnetic fields, and their thermal expansion. It is demonstrated that the studied properties exhibit a number of anomalies due to a transition from the antiferromagnetic semiconducting state to the ferromagnetic metallic state upon suppression of charge ordering.

The magnetostriction of Pr0.6Ca0.4MnO3 and Pr0.65Ca0.28Sr0.07MnO3 manganite crystals is investigated in pulsed magnetic fields up to 250 kOe. The field-induced phase transitions from the charge-ordered antiferromagnetic (paramagnetic) state to the metallic ferromagnetic state are studied. It is found that these transitions are accompanied by abrupt negative jumps in the longitudinal and transverse magnetostrictions and a strong hysteresis at low temperatures. The threshold fields of transitions are determined, and the H-T phase diagrams are constructed.

A study is reported on phase transitions in the La1−x SrxMnO3 system, both spontaneous and induced by a pulsed magnetic field of up to 250 kOe, accompanied by anomalies in magnetoelastic properties. The temperatures of the polaron (charge) and magnetic ordering, as well as those of structural transitions, are observed to be in good agreement with the results obtained by other methods. Jumps in the field dependence of longitudinal and transverse magnetostriction associated with field-induced orbital ordering have been found. A strong temperature dependence of the corresponding threshold fields is observed.

The magnetic and magnetoelastic properties of single crystals of electron-doped rare-earth manganites La1−x Sr x MnO3 are studied. Phase transitions from the A-type antiferromagnetic phase to the C-type anti-ferromagnetic phase in a strong magnetic field are revealed in La1−x Sr x MnO3 manganites with a strontium content x = 0.65. A similar phase transition is observed in manganites with a strontium content x = 0.8, at which the La0.2Sr0.8MnO3 manganite is assumed to transform from the C-type antiferromagnetic phase to the G-type antiferromagnetic phase.

Measurements of the magnetic and magnetoelastic properties of Nd0.5Ca0.5MnO3, Nd0.55Ca0.45MnO3, and Nd0.6Ca0.4MnO3 single crystals have revealed correlations between the observed anomalies in magnetization and magnetostriction associated with suppression of the antiferromagnetic phase and charge ordering by a strong magnetic field followed by transition to the ferromagnetic state. H-T phase diagrams are constructed.

By studying the magnetic and magnetoelastic properties, it is established that, as the temperature is lowered, Sm1−xSrxMnO3 single crystals (x=0.5, 0.55) undergo spontaneous phase transitions from the paramagnetic to a local charge-ordered state at Tco=220 K and to an A-type antiferromagnetic state at TN=175 K. It is shown that strong magnetic fields (Hcr ∼ 200 kOe) break up the antiferromagnetic order and charge ordering and drive a phase transition to a conducting ferromagnetic state. H-T phase diagrams are constructed for single crystals with x=0.5 and 0.55.

Anomalon in temperature dependence of the magnetic moment (FexCr1−x)2O3 single crystal has been observed which can be explained by antiparallel orientation of the mean weakly-ferromagnetic moments of the d subsystems (weak ferromagnetism). The disappearance of the linear magneto-electric effect for x=0.1 below 45 K is explained by a spontaneous phase transition from a conical spiral to a cycloidal spin structure, which is found to agree with a thermodynamic treatment.