Characterization of the charge ordering state by maximum entropy method

The phase diagram and crystal chemistry of strontium-doped rare earth cobaltates: Ln2−xSrxCoO4+δ (Ln=La–Dy)

“…Prior to this study very few examples of K 2 NiF 4 cobaltates containing cobalt oxidations states > Co(III) have been reported. Although not explicitly discussed in their work, the production of La 0.6 Sr 1.4 CoO 3.94 by Sánchez-Andújar and Senaris-Rodriguez [21], implies a mixture of (72%) Co 3+ and (28%) Co 4+ .…”

“…Sánchez-Andújar and Senaris-Rodriguez [21] recently conducted a limited exploration of the solid solution range of Ln 2−x Sr x CoO 4 for Ln = La, Nd, and Gd. They did not examine any compositions below x = 1.0 and found an upper boundary to the solid solution of x = 1.4 for Ln = La, x = 1.3 for Ln = Nd, and x = 1.2 for Ln = Gd.…”

“…More recently, a single crystal neutron diffraction study of La 2 NiO 4.14 by Paulus et al confirmed the presence of an interstitial oxygen at the (1/4, 1/4, 1/4) site a tetragonal (F4/mmm, [30]. Of the Ln 2−x Sr x CoO 4+δ compounds studied by Sánchez-Andújar and Senaris-Rodriguez [21], only the Ln = La 3+ members of the family were investigated using TGA. They found that samples prepared in air at 975 • C were slightly oxygen deficient, with an oxygen contents ranging between 4.00 for x = 1.00 composition to 3.94 for x = 1.40 composition.…”

“…With the exception of the La 2−x Sr x CoO 4 compounds [16][17][18][19][20][21], other rare earth cobaltbased K 2 NiF 4 phases have received relatively little attention [21,22]. There has been substantial debate on the electronic ground state configurations of a range of rare earth cobaltates relating to the existence of the intermediate spin-state.…”

Influence of the dimensionality of the structure and the nature of the rare earth on the magneto-transport properties of Nd1−xSr1+xCoO4 (0≤x≤0.30)

“…In this work we focus in the properties of the bidimensional Nd series Nd 1−x Sr 1+x CoO 4 , for which to our knowledge, the only information available in the literature refers to its synthesis and structural characterization [15,16].…”