Domain structure of the antiferromagnetic insulating state in Nd0.5Sr0.5MnO3

Abstract

Optical reflectivity studies of the ferromagnetic metal (FMM) to antiferromagnetic insulator (AFI) phase transition are performed on Nd0.5Sr0.5MnO3 manganite in a wide temperature and magnetic field range. The formation of a domain structure in the AFI state during the FMM−AFI phase transition is observed. It is shown that the two types of domains observed are energetically equivalent states. On the basis of the experimental results and symmetry analysis we conclude that these domains are crystal twins. The twin domain structure of the AFI state in the Nd0.5Sr0.5MnO3 is visible in reflected unpolarized light due to a different tilting of the surface in the domains. The two-phase domain structure FMM+AFI formed in the vicinity of the phase transition is also studied. It is found that a thermodynamically equilibrium two-phase stripe domain structure does not develop. The absence of the magnetic intermediate state is due to the large energy of the interphase wall, which results in the stripe structure period being much larger than the size of the sample.

Observation of the magnetic structure in manganites by the high-resolution Bitter technique

“…Especially interesting is a colossal magnetoresistance associated with the ferromagnetic (FM) metallic-to-antiferromagnetic (AF) insulating-state phase transition [1]. Some experiments have revealed FM-AF phase separation [2] and multidomain ferromagnetic structures [3,4]. The transition is governed by many factors, the most important of which are doping concentration, magnetic field and temperature.…”

Magnetic phase transitions in the system La1−xBixMnO3+λ

“…These compounds contain ions with orbital degeneracy or Jahn-Teller (JT) ions (in our case Mn 3+ ) [1]. Thus their properties differ appreciably from those of the corresponding substances with the «ordinary» ions: the crystal structure turn out to be distorted, structural phase transitions and transitions in a magnetic subsystem [2][3][4][5][6] are frequently observed in them, and in many cases they have anomalously strong magnetic anisotropy and magnetostriction [7,8]. Such phenomena are connected with an interaction of the JT ions and are called the cooperative Jahn-Teller effect (CJTE).…”

Two-dimensional growth, anisotropic polaron transport, and magnetic phase segregation in epitaxial Nd0.52Sr0.48MnO3 films

“…1 Therefore, the two magnetic phases are segregated into FM and AFM clusters and coexist for T ഛ T N . 22,29 The main evidence for magnetic phase separation ͑or a magnetic clustering͒ is ZFC/FC M͑T͒ splitting, which was observed for all the NSMO/STO films and for the NSMO/ LAO film with d ϳ 50 nm over a wide range of applied magnetic fields ͑see Figs. 4 and 5͒.…”