Spin-flop and magnetodielectric reversal in Yb substituted GdMnO₃

Abstract

The evolution of various spin structures in Yb doped GdMnO<sub>3 </sub>distorted orthorhombic perovskite system was investigated from their magnetic, dielectric and magnetodielectric characteristics. The Gd<sub>1-<i>x</i></sub>Yb<sub><i>x</i></sub>MnO<sub>3</sub> (0 ≤ <i>x</i> ≤ 0.15) revealed an enhanced magnetodielectric coupling when their magnetic structure is guided from <i>ab</i> to <i>bc</i>-cycloidal spin structure upon Yb doping. The compounds exhibit magnetic field and temperature controlled spin-flop from <i>c</i> to <i>a</i>-axis. Additionally, magnetodielectric reversal is observed for <i>x</i> = 0.1 sample which depends on both magnetic field and temperature. The resultant correlation between magnetic and electric orderings is discussed in the frame of symmetric and antisymmetric exchange interaction models. These findings provide further insight in understanding the magnetoelectric materials and importantly show a way to tune the magnetic and magnetodielectric properties towards better application potential.

Multiferroicity in a spin-chain compound, Tb2BaCoO5, with exceptionally large magnetodielectric coupling in polycrystalline form

“…Such a feature is absent above TN, e.g., at 40 K. These features below TNinitial weak field dependence, followed by a sharp upturn, a peak and reversal in magnitudemimic those seen for 10 atomic percent Yb doped GdMnO3 (ref. 29 ]. In this case, it was proposed that both symmetric exchange interaction (resulting in exchangestriction) and asymmetric DM interaction may be operative.…”

Investigation of field-controlled magnetocaloric switching and magnetodielectric phenomena in spin-chain compound Er2BaNiO5

“…Further, this correlation between the magnetic and electrical properties ensures the intrinsic nature of the MD effect. In this context, it should be mentioned that several factors such as M-W effect, magnetoresistance or intrinsic coupling between electric and magnetic orderings, can cause to induce MD effect in any system [9,39]. However, the M-W effect can be ruled out easily as the MD phenomenon in the present sample is more pronounced in the temperature range of 20 K-40 K, where the M-W effect is less active compared to the higher temperatures.…”

“…In figure 6(a), we show the variation of dielectric constant (ε r ′ ), as a function of temperature at various frequencies from 10 kHz to 1 MHz under zero magnetic field. It indicates a shift in ε r ′ toward higher temperature with increasing frequency (indicated by the arrow in figure 6(a)), which mostly suggests an extrinsic behavior such as Maxwell-Wagner (M-W) relaxation phenomenon [9,39,40]. It is well known that all polycrystalline samples must have both grain and grain boundary contributions to their dielectric spectra.…”

“…In this family, the magnetoelectric (ME) multiferroics are the most important members for their cross-coupling between the magnetic and ferroelectric (FE) orderings, which provides extra degrees of freedom and makes them highly suitable candidates for fundamental studies and technological implications in novel data storage devices and spintronics [1,[4][5][6][7]. However, despite a huge number of attempts, the success of achieving single phase ME multiferroics is limited, which inspires researchers to find an alternative system of materials possessing a correlation between magnetic and dielectric properties, with a high value of magnetodielectric (MD) effect (change in dielectric constant under external magnetic field) [8][9][10][11][12]. On the other hand, materials with a giant magnetocaloric effect (MCE) are important for their potential application in magnetic refrigeration technology [13,14].…”

Strain relaxation dynamics of multiferroic orthorhombic manganites

“…Against this wider view of strain coupling, the primary objective of the present study was to investigate the dynamics of strain relaxation associated specifically with the multiferroic behavior of GdMnO 3 and TbMnO 3 . There are numerous studies of the temperature and frequency dependence of the dielectric responses of both materials to ac electric fields (including [2,3,[17][18][19][20][21][22][23][24][25][26][27][28]) and one of the dynamical response to an ac magnetic field [29], but there appear to be no data in the literature for the elastic/anelastic response to ac stress. Significant differences have been observed between acoustic resonance spectra of hexagonal YMnO 3 and orthorhombic Sm 0.6 Y 0.4 MnO 3 , however, and these provided evidence of a strain relaxation process that is specific to the multiferroic orthorhombic structure [30,31].…”