相关论文: Microscopic spin interactions in the CMR manganite…
In this work, we report an atomic scale study on the ferromagnetic insulator manganite LaMnO$_{3.12}$ using $\gamma-\gamma$ PAC spectroscopy. Data analysis reveals a nanoscopic transition from an undistorted to a Jahn-Teller-distorted local…
A systematic study of the electronic structure in perovskite manganites is presented. The effective Hamiltonian is derived by taking into account the degeneracy of $e_g$ orbitals and strong electron correlation in Mn ions. The spin and…
Spin-electronic devices are poised to become part of mainstream microelectronic technology .Downsizing them, however, faces the intrinsic difficulty that as ferromagnets become smaller, it becomes more difficult to stabilize their magnetic…
We present a new type of colossal magnetoresistance (CMR) arising from an anomalous collapse of the Mott insulating state via a modest magnetic field in a bilayer ruthenate, Ti-doped Ca$_3$Ru$_2$O$_7$. Such an insulator-metal transition is…
We demonstrate that magnetic phase separation and competing spin order in the colossal magnetoresistive (CMR) manganites can be directly explored via tuning strain in bulk samples of nanocrystalline La$_{1-x}$Ca$_x$MnO$_3$. Our results show…
Ferromagnetic (FM) manganites, a group of likely half-metallic oxides, are of special interest not only because they are a testing ground of the classical doubleexchange interaction mechanism for the colossal magnetoresistance, but also…
A tight binding parametrization of local spin density functional band theory is combined with a dynamical mean field treatment of correlations to obtain a theory of the magnetic transition temperature, optical conductivity and T=0 spinwave…
The spin correlations of the bilayer manganite $La_{1.2}Sr_{1.8}Mn_{2}O_{7}$ have been studied using neutron scattering. On cooling within the paramagnetic state, we observe purely two-dimensional behavior with a crossover to…
First-principles calculations of the epitaxial-strain phase diagram of perovskite SrCoO$_{3}$ are presented. Through combination of the large spin-phonon coupling with polarization-strain coupling and coupling of the band gap to the polar…
Colossal magnetoresistance (CMR) emerges from intertwined spin and charge degrees of freedom in the form of ferromagnetic clusters also known as trapped magnetic polarons. As a result, CMR is rarely observed in antiferromagnetic materials.…
Neutron scattering results are presented for spin-wave excitations of three ferromagnetic metallic $A_{1-x}A^{\prime}_{x}$MnO$_3$ manganites (where $A$ and $A^\prime$ are rare- and alkaline-earth ions), which when combined with previous…
We present a detailed magnetic study of the perovskite manganite Pr0.7Ca0.3MnO3 at low temperatures including magnetization and a.c. susceptibility measurements. The data appear to exclude a conventional spin glass phase at low fields,…
We have investigated the interplay between the metal-insulator transition and ferromagnetism in $({\rm III}_{1-x},{\rm Mn}_x){\rm V}$ ferromagnetic semiconductors. Our study is based on a model in which $S=5/2$ Mn local moments are…
In metal-insulator transition materials, a small perturbation can shift the delicate balance between competing or coexisting electronic phases, leading to dramatic changes of the material's properties. Using La0.7Sr0.3MnO3, a prototypical…
Antiferromagnetic spintronics is an emerging field; antiferromagnets can improve the functionalities of ferromagnets with higher response times, and having the information shielded against external magnetic field. Moreover, a large list of…
The paramagnetic insulator to ferromagnetic metal transition in Lanthanum manganites and the associated magnetoresistive phenomena is treated by considering the localization due to random hopping induced by slowly fluctuating spin…
Current-induced switching from metallic to insulating state is observed in phase-separated states of (La_{1-y}Pr_y)_{0.7}Ca_{0.3}MnO_3 (y=0.7) and Nd_{0.5}Ca_{0.5}Mn_{1-z}Cr_zO_3 (z=0.03) crystals. Application of magnetic fields to this…
We investigate the electrical and magneto-transport properties of Pt-C granular metals prepared by focused-electron-beam induced deposition. In particular, we consider samples close to the metal-insulator-transition obtained from as-grown…
Materials with strong magnetoresistive responses are the backbone of spintronic technology, magnetic sensors, and hard drives. Among them, manganese oxides with a mixed valence and a cubic perovskite structure stand out due to their…
Magnetoresistance (MR) and magnetization (d.c and a.c) measurements have been carried out on the manganites, (La0.7-2xEux)(Ca0.3Srx)MnO3 (0.05<x<0.15), in the temperature range of 5K-320K. At 5K, an unusually large MR of almost 98% is…