Double perovskites half-metallicity

In the last decade, study of double perovskites has accelerated with the discovery of tunneling magnetoresistive (TMR) effects in Sr2FeMo06.i56N. Both the magnetism and transport in these oxides is strongly influenced by the cationic nature and the order/disorder of the ions at the B-site. Ferromagnetism and half-metallic properties are often... 

Tlie plienomenon of half-metallicity has gained much interest in order to understand the unusual band structures in various classes of materials and their potential applications in future electronic devices. For example, zinc blend pnictides and chalcogenides e.g. CrAs) are another class of non-oxide materials (apart from Heuslers) in addition to the many oxide classes that are potentially half-metallic materials. Alkali metal doped rare earth oxomanganates, (REi- A MnOs), rutile-Cr02, spinel-Fe304 and Sr2peMo06 double perovskite oxide are examples of important half-metallic oxides. 

Due to its metallic and FM property, similar to double perovskites (see later), Cr02 is of great interest to material scientists and physicists. A computed band structure of Cr02 is shown in Figure 5.6. The Fermi level crosses the majority-spin band while it lies in a gap of the minority-spin density of states (DOS). Therefore, Cr02 is half-metallic on the basis of electronic structure calculations. The same band structure has been reproduced by several groups since it was first demonstrated by... 

Half-Metallic Antiferromagnetic (HMAFM) Double Perovskites... 

As it was already mentioned, the ordered double perovskite St2FeRe06 is also predicted to have a half-metallic ground state. The observed Ms of 2.7 pB/f-u. at 4.2 K is smaller than expected (3 pB/f-u.) for an antiferromagnetic coupling between Fe (d ) and Subsequent to the... 

The magnetic properties of half-metallic Sr2FeMo06 and related double perovskites cannot be explained on the basis of conventional and... 

While an ordered sample ( 91%) of Sr2FeMo06 showed a sharp low-field MR response, it was much lower in a partially disordered ( 31%) sampleJ Therefore, its absence in the disordered phase indicates the obliteration of HMF property due to large AS disor-der. Thus, ordering in double perovskite is crucial for the true nature of the half-metallic ground state and the intrinsic properties of the material. 

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