Field induced changes in cycloidal spin ordering and coincidence between magnetic and electric anomalies in BiFeO3 multiferroic

Abstract

The ZFC and FC magnetization dependence on temperature was measured for BiFeO 3 ceramics at the applied magnetic field up to µ 0 H = 10 T in 2 K ÷ 1000 K range.The antiferromagnetic order was detected from the hysteresis loops below the Neel temperature T N = 646 K. In the low magnetic field range there is an anomaly in M(H), probably due to the field-induced transition from circular cycloid to the anharmonic cycloid.At high field limit we observe the field-induced transition to the homogeneous spin order.From the M(H) dependence we deduce that above the field H a the spin cycloid becomes anharmonic which causes nonlinear magnetization, and above the field H c the cycloid vanishes and the system again exhibits linear magnetization M(H). The anomalies in the electric properties, ε'(T), tanδ(T), and σ(T), which are manifested within the 640 K ÷ 680 K range, coincide to the anomaly in the magnetization M(T) dependence, which occurs in the vicinity of T N = 646 K. We propose to ascribe this coincidence to the critical behaviour of the chemical potential µ S , related to the magnetic phase transition.

Dissipationless spin current between two coupled ferromagnets

“…The typical spiral wave length is ∼ 100 lattice constants, so D ∼ 1meV if J ∼ 100meV, which means |B| ∼ 10T can make all the spins parallel, consistent with that reported in Ref. 83. According to Eq.…”

Analysis of multi-domain ferroelectric switching in BiFeO3 thin film using phase-field method

“…This coupling consequently leads to the modulation of ferromagnetic/antiferromagnetic ordering via ferroelectric polarization switching. In experiments, piezoresponse force microcopy (PFM) and transmission electron microscopy (TEM) are commonly used to investigate the ferroelectric domain structures [6][7][8][9][10][11][12] , as well as the electric-field-induced domain switching [13][14][15][16][17] . Statistical analysis of interfacial polarization angles has been done based on PFM domain mapping results, showing that 71° domain wall is the dominant one 13 .…”

Peculiarities of 57-Fe NMR Spectrum in Micro- and Nanocrystalline Europium Orthoferrites

“…Because of this spin distribution, low temperature NMR spectrum of bulk BiFeO 3 consists of wide (∼1 MHz) line with two maxima [26]. As it was shown in a number of works, this cycloida is supressed by application of a strong external magnetic field, by producing strained thing films of this material, by substituting of Bi by rare-earth elements, and other methods [27,28,29,30,31]. Earlier, 57 Fe MNR spectra have been obtained for La doped Bi 1−x La x FeO 3 and it was shown that at x = 0.3 NMR line has only one broad peak; at x ≥ 0.9 this peak becomes narrow and shifts to high frequencies [32].…”