Charge-disproportionation-induced magnetic glassy behavior inLa0.5Ca0.5FeO3−δ

57Fe and 151Eu Mössbauer study of charge disproportionation and magnetic properties in Eu1/3Sr2/3FeO3

“…It can be seen that even under a field of 50 kOe, the magnetization does not saturate. It still has a tendency to increase, which is corresponding to the main antiferromagnetic ordering of spins [7,8]. It was reported that the Fe-O bond length and the Fe-O-Fe angel are two important structural properties which affect the weak ferromagnetism in iron perovskite [4,5].…”

“…This phenomenon was generally ascribed to electronically driven mechanism, and the oxygen holes play an important role. Moreover, phase separation in these systems usually occurs, which leads to cluster glass behavior and the corresponding superparamagnetism or magnetic relaxation behaviors [8,14]. The dynamics of cluster glass behavior and the relationship between the phase separations, cluster properties and CD in these systems are still open questions.…”

“…The iron perovskite-type oxides with rare earth and alkaline earth atoms are interesting because of their unique properties such as charge disproportionation(CD) [1][2][3][4][5][6][7][8], charge and orbital ordering [2,4,9,10] and cluster glass behaviors [11][12][13]. The first example of CD transition in perovskite was CaFeO 3 at 290 K at which the Fe 4+ discrete as Fe 3+ and Fe 5+ , accompanied by a structural transition from Pbnm in the normal state to P2/n [6].…”

“…The oxygen deficiencies are calculated as 0.033 and the molecular formula can be deduced as Eu 1/3 Sr 2/3 FeO 2.967 for charge balance consideration. The analysis receives support from the Mössbauer study of similar perovskites [7][8][9][10]13]. The Mössbauer spectra measured below 90 K are composed of only magnetic sextets, which can be resolved into two subcomponents, which can be assigned to Fe 3+ and Fe 5+ due to the possible different neighboring environment for their parameters are typical values of Fe 3+ and Fe 5+ [13].…”

Structural, multiferroic properties and enhanced magnetoelectric coupling in Sm1−xCaxFeO3

“…While at present most of the studies of the technological applications of the Ln 1À x Ca x FeO 3À δ family of materials have focused on their catalytic ability for carbon monoxide and methane oxidation, similar classes of perovskite related oxide materials, such as rare earth strontium cobaltates, have been investigated to use as cathode materials for solid oxide fuel cells [1], ceramic membranes for high temperature oxygen separation, and high k-dielectric materials [2,3] and magnetic sensors [4]. For significant amount of Ca doping, charge balance is maintained by a combination of formation of Fe 4 þ and oxygen vacancies (δ) [5].…”