High temperature enthalpies and heat capacities of YbMnO3 and YMnO3

Magnetic Properties of LnMnO3 (Ln=Ho, Er, Tm, Yb, and Lu)

“…The samples were prepared by a solid-state reaction in air as in the previous works (6,(8)(9)(10). Stoichiometric mixtures of Ln 2 O 3 (Ln=Ho, Er, Tm, Yb, and Lu) and Mn 2 O 3 (3N-4N, Soekawa) were thoroughly ground, pressed into pellets and fired in air at 13001C for 24 h. The firing was repeated two to three times with intermediate grindings.…”

“…Magnetization measurements for Ln=Yb and Lu showed antiferromagnetic transitions at T N =82 and 86 K, respectively, where only the Yb 3+ ion has a localized 4f moment (4f 13 ) (8). For the other compounds, to the authors' knowledge no magnetization data have been reported, though thermodynamic properties such as heat capacity have been investigated for some of the systems (9,10). In this paper, magnetic data for Ln=Ho, Er, Tm, Y, and Lu, obtained mainly from DC magnetization measurements, are presented.…”

“…The structure changes to a hexagonal P6 3 cm structure for the heavier lanthanides of Ln=Ho-Lu as well as Ln=Y and Sc, containing two-dimensional triangular Mn-O lattices (4)(5)(6)(7)(8)(9)(10). A neutron diffraction study for Ln=Ho, Er, Tm, Lu, and Sc revealed that these compounds showed antiferromagnetic transitions of the Mn 3+ moments with Ne´el temperatures (T N ) of B70-130 K, below which a noncollinear 1201 spin structure was observed (5).…”

P—T—X phase diagram of the Yb—Mn—O system

“…where T is temperature, K; and is the oxygen pressure, Pa. (1) and (3), respectively; lines b, d, c, and e correspond to the data in [6][7][8][9]. .…”

“…Line c was obtained from the data in [8] by recalculation with taking into account the temperature dependences of heat capacities of all the compounds involved in dissociation reaction (3); as the reference point (d) in [8], the data from [9] obtained at 1473 K were taken. Some differences between our findings and the data in [6][7][8][9] (lines b, c, and e in Fig. 3) can be associated with a change in the oxygen nonstoichiometry and cationic composition of the YbMnO 3 phase in different temperature ranges.…”