RETRACTED: Coupling between Ho and Mn/Cr moments and its influence on the structural and magnetic properties of HoMn1−xCrxO3 (0 < x ≤ 1) compounds

Spin reorientation behaviour and dielectric properties of Fe-doped h-HoMnO3

“…Further, we find a significant enhancement in the spin reorientation temperature, T SR with Fe doping while the change in T Ho,Mn N is minimal or absent, which appears to suggest that the occurrence of T SR is independent of Ho ordering, which is not in agreement with the theoretically proposed model [14,35]. The increase in the value of T SR with Fe doping is also in contrast with the earlier observations of suppression of T SR with doping [36][37][38], magnetic field [39,40], and external pressure [41]. The suppression of the dielectric constant below T N is further shown to scale linearly with the square of the Mn sublattice magnetization, in accordance with Landau theory.…”

“…Earlier results have also shown that perturbations like external pressure [41] and magnetic field [39,40] lead to lowering of T SR . However T SR can either be increased or decreased with doping different ions such as Ga [60], Er [36], Y [37] and Cr [38]. In earlier works [41,61], the variation of T SR with pressure has been correlated with the suppression of the c-axis.…”

“…Figure 2 shows the increase in the concentration of the orthorhombic phase as a function of dopant concentration (x), obtained from the Rietveld analysis of the neutron diffraction data. As compared to other trivalent dopants on the Mn site such as Cr 3+ [38] or Co 3+ [45], Fe 3+ maintains the stability of the hexagonal structure up to a higher degree of dopant concentration. This is probably due to the similar ionic sizes of the Mn 3+ and the Fe 3+ ions in the five coordination (0.58 Å) and the six-fold coordination states (0.645 Å).…”

Spin phonon coupling in Mn doped HoFeO3 compounds exhibiting spin reorientation behaviour

“…The ionic radii of Fe 3+ and Mn 3+ being nearly the same in HS state and 6 coordination, the increasing difference between a and c indicates towards the increase of static Jahn-Teller distortion in the a-c plane with x. Similar trend is observed in cases where a non-JT ion like Cr 3+ [19], Fe 3+ [11] is substituted with a JT ion like Mn 3+ . The effect of J-T distortion is also reflected in the increasing inequality of the bond lengths as shown in figure 1(c).…”

“…Following the representation theory, for the Pnma space group ( k = 0) there are eight possible irreducible representations (IR) (Г 1 -Г 8 ) on consideration of moments on the rare earth site alone. Only four of them are valid on consideration of moments on the transition metal ion site and rare earth ion as well [4,19]. In our refinement the basis vectors were obtained using the SARAh program [20].…”