Magnetic and spectral studies of Er2BaNiO5 and other rare earth nickelates

Magnetoelectric coupling in the Haldane spin-chain system Dy2BaNiO5

“…These critical magnetic field values (H c ) correspond to the maxima in dM/dH. It is important to note that a small but clear hysteresis is observed at H c2 and H c3 which was not noticed in previous studies [12,16]. This establishes first-order nature of these transitions.…”

“…In this article, we focus our attention on the spin-chain systems of the type R 2 BaNiO 5 (R= Rare-earths) [3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19], which do not exhibit geometrically frustrated magnetism. Among spin-chain systems, rare earth nickelates (spin, S = 1) have drawn great interest in recent years due to the observation of Haldane gap [20 ] even in the long range magnetically ordered state [4,11,[17][18][19] for magnetic moment containing R-members.…”

“…The magnetic structure is commensurate k(1/2, 0, 1/2) in the absence of an external magnetic-field (H). It may be noted that most of the compounds of this family have been known to exhibit only two magnetic-field-induced transitions below T max [12,16].…”

“…However, to the best of our knowledge, there is no further report on the behavior of ε' vs T (except for Y 2 BaNiO 5 ) and ε' vs H for any member of this series. As most of the R 2 BaNiO 5 compounds show magnetic-field-induced transitions [12,16] and are highly insulating at low temperatures, it would be interesting to study magnetic and dielectric properties (as a function of T and H) to explore the existence of ME coupling in these systems. In this series, T N varies with rare-earth ionic radius and maximum T N (∼65K) is observed for R = Tb.…”

Crystal field and magnetic ordering in the Haldane-chain compound Er2BaNiO5 as studied by optical spectroscopy

“…Neutron scattering [2] and spectroscopic [3] experiments revealed a magnetic ordering of Er 2 BaNiO 5 at T N ≈ 34 K.…”