Ferromagnetic domain structure ofLa0.78Ca0.22MnO3single crystals

Abstract

The magneto-optical technique has been employed to observe spontaneous ferromagnetic domain structures in La 0.78 Ca 0.22 MnO 3 single crystals. The magnetic domain topology was found to be correlated with the intrinsic twin structure of the investigated crystals. With decreasing temperature the regular network of ferromagnetic domains undergoes significant changes resulting in apparent rotation of the domain walls in the temperature range of 70-150 K. The apparent rotation of the domain walls can be understood in terms of the Jahn-Teller deformation of the orthorhombic unit cell, accompanied by additional twinning.

Crystallographic direction dependence of electrical-transport, magneto-transport, magnetic and thermal properties of La 0.7 Ca 0.3 MnO 3 single crystal

“…It is worth to mention that the anisotropic resistivity is responsive to the applied magnetic field and it is more effective than application of pressure in varying the electrical transport properties of manganites. This observed behavior of magnetic field dependence of resistivity in both [31]. There is no easy explanation for the decrease of ρab below 150 K along the abplane.…”

Metastable resistivity states and conductivity fluctuations in low-doped La1−xCaxMnO3 manganite single crystals

“…2,3,5,6 Presence of two ferromagnetic phases with different orbital order and electronic properties 3,4,7 leads to appearance of metastable states with markedly different resistivity. [8][9][10][11][12][13][14][15][16] Metastable states are characterized by history dependent conductivity, pronounced relaxation of magnetization and resistivity, memory effects in electric resistance and magnetization, and strong 1/f-type conductivity noise frequently accompanied by non-Gaussian fluctuations.…”

“…14- 16 We have for some time concentrated on investigations of metastable states induced by electric field/current procedures. [8][9][10][11][12] We have used both continuous current sweeps and short current pulses to create low and high resistivity metastable states in LCMO single crystals and thin films. While relatively slow current sweeps with progressively increasing amplitude tend to decrease sample resistivity, application of bias pulses at low temperatures have much stronger effect and increases the resistivity by orders of magnitude.…”

“…However, with elapsing time, LCMO samples spontaneously evolve towards higher resistivity states and it becomes progressively more difficult to enforce metastable states and/or to rejuvenate them. 11 Such ageing effects impose still not fully answered question about the ultimate equilibrium state of low-doped manganites.…”

Symmetry Pattern and Domain Wall Structure in GdFeO3Perovskite Type

“…This distortion is commonly encountered in perovskite-type materials, for example in: rare-earth aluminates [2][3][4], YAlO 3 [5], gallates [6][7][8], ferrites [9][10][11], titanates [12,13] under normal conditions and in some silicates at high pressures [14], causing ferroelastic properties as well as the appearance of antiphase boundaries [15,16]. The behavior of domains can strongly influence materials qualities, for example, the configuration of the magnetic domain structure in the solid state solution of rare-earth manganites [17]. Interactions of point defects with domain boundaries determine a whole series of physical properties in such materials with perovskite-type structure, recently used for different technical applications.…”