Journal ArticleDOI
Anneal‐tunable Curie temperature and transport of La0.67Ca0.33MnO3
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TLDR
In this article, resistivity measurements on a La0.67Ca0.33MnO3 film are reported for a series of argon anneals at successively higher temperatures.Abstract:
Resistivity measurements on a La0.67Ca0.33MnO3 film are reported for a series of argon anneals at successively higher temperatures. Tc, the ferromagnetic ordering temperature, increases uniformly with increasing annealing temperature and annealing time. Hence, Tc can be tuned by appropriate annealing. In order to fully anneal these samples, i.e., achieve bulk properties, it proves sufficient to anneal them in argon. Further annealing in oxygen produces only minor changes in the resistivity. Data from Tc up to 1200 K show activated conduction with ρ=BTeEa/kT, the temperature dependence predicted by the Emin–Holstein theory of adiabatic polaron hopping. Their model fits both data from the partially annealed and fully annealed samples better than the variable range hopping or semiconductor models which have been used by previous workers. The activation energy Ea and resistivity coefficient B decrease with increasing maximum anneal temperature. These changes, together with the increase in Tc, are consistent w...read more
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Ferromagnetic manganites: spin-polarized conduction versus competing interactions
TL;DR: In this paper, a phenomenological approach is proposed to systematically outline some fundamentals and key experiments on ferromagnetic manganites, partially with respect to thin film structures, followed by experiments on spin-polarized tunnelling.
Journal ArticleDOI
Colossal magnetoresistance of spin-glass perovskite La0.67Ca0.33Mn0.9Fe0.1O3
TL;DR: The magnetic and magnetotransport properties of perovskite La0.67Ca0.33Mn0.9Fe0.1O3 have been investigated, and the spin-glass behavior with a spin freezing temperature of 42 K has been well confirmed for this compound.
Journal ArticleDOI
Effect of sintering temperature on electrical transport properties of La0.67Ca0.33MnO3
G. Venkataiah,D.C. Krishna,M. Vithal,S.S. Rao,S. V. Bhat,V. Prasad,S.V. Subramanyam,P. Venugopal Reddy +7 more
TL;DR: In this article, a systematic investigation of lanthanum-based manganite, La0.67Ca0.33MnO3, has been undertaken with a view to understand the influence of varying crystallite size, in the nanoscale, on various physical properties.
Journal ArticleDOI
Influence of A-site cation mismatch on structural, magnetic and electrical properties of lanthanum manganites
TL;DR: In this paper, the influence of cation mismatch on magnetic as well as electrical behavior of manganite perovskites has been investigated with X-ray diffraction (XRD) data, and it has been concluded that the electrical resistivity data in the ferromagnetic (metallic) regime $(T T_P)$ also influences $T T _C$ values.
Journal ArticleDOI
Self-doped lanthanum manganites as a phase-separated system: Transformation of magnetic, resonance, and transport properties with doping and hydrostatic compression
V. D. Doroshev,V. A. Borodin,V. I. Kamenev,Anton S. Mazur,T. N. Tarasenko,Alexandr Tovstolytkin,S. V. Trukhanov +6 more
TL;DR: The magnetic, resonance, and electric properties of LaxMnO3+δ (0.815≤x≤1.0) polycrystalline samples have been studied in the temperature range of 77-370 K and at high pressures of up to 11.5 kbar.
References
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Book
Introduction to Ceramics
TL;DR: In this paper, the authors present a model for the development of the MICROSTRUCTURE in CERAMICS based on phase transformation, glass formation and glass-Ceramics.
Journal ArticleDOI
Studies of polaron motion: Part II. The “small” polaron
TL;DR: In this article, the authors considered the case in which the electronic-overlap term of the total Hamiltonian is a small perturbation, and showed that the probability of off-diagonal transitions goes up exponentially with increasing temperature.
Journal ArticleDOI
Lattice effects on the magnetoresistance in doped lamno3
Harold Y. Hwang,Harold Y. Hwang,Sang-Wook Cheong,Radaelli Pg,M. Marezio,M. Marezio,Bertram Batlogg +6 more
TL;DR: The results show that the notion of ``double exchange'' must be generalized to include changes in the Mn-Mn electronic hopping parameter as a result of changes inThe Mn-O-Mm bond angle.
Journal ArticleDOI
Studies of small-polaron motion IV. Adiabatic theory of the Hall effect
David Emin,T. Holstein +1 more
TL;DR: In this article, the effect of the magnetic field on the motion of a small polaron in the presence of a magnetic field is studied in the adiabatic approximation of the two-dimensional molecular crystal model of Friedman and Holstein.
Journal ArticleDOI
Colossal magnetoresistance of ferromagnetic manganites: Structural tuning and mechanisms.
Josep Fontcuberta,Benjamín Martínez,A. Seffar,S. Piñol,José Luis García-Muñoz,Xavier Obradors +5 more
TL;DR: The amplitude $\ensuremath{\rho}(T,H)$ and temperature ${T}_{M}$ and CMR are found to be controlled by the radius of the lanthanide $({L}^{3+})$ which modifies the bending of the Mn-O-Mn bond.