Using spin-polarized scanning tunneling spectroscopy, we reveal how the standing wave patterns of confined surface state electrons on top of nanometer-scale ferromagnetic Co islands on Cu(111) are affected by the spin character of the responsible state, thus experimentally confirming a very recent theoretical result. Furthermore, at the rim of the islands a spin-polarized state is found giving rise to enhanced zero bias conductance. Its polarization is opposite to that of the islands. The experimental findings are in accordance with ab initio spin-density calculations.

Energetics of the fcc (γ) -bcc (α) lattice transformation by the Bain tetragonal deformation is calculated for both magnetically ordered and paramagnetic (disordered local moment) states of iron. The first-principle computational results manifest a relevance of the magnetic order in a scenario of the γ -α transition and reveal a special role of the Curie temperature of α-Fe, TC , where a character of the transformation is changed. At a cooling down to the temperatures T < TC one can expect that the transformation is developed as a lattice instability whereas for T > TC it follows a standard mechanism of creation and growth of an embryo of the new phase. It explains a closeness of TC to the temperature of start of the martensitic transformation, Ms.PACS numbers: 61.50. Ks, 64.70.kd, 75.30.Et, 75.50.Bb, 71.20.Be Deeper understanding of mechanisms of polymorphous γ -α transformation in iron and its alloys is of fundamental importance for both metallurgical technologies [1,2] and for a general theory of phase transitions in solids [3,4,5]. Despite numerous investigations an issue of a mechanism of a new phase nucleation in the course of γ -α transformation remains open (see, e.g., discussion in Ref. 4).

-Electron density of states and band structure of crystalline solids. PACS. 75.25.+z -Spin arrangement in magnetically ordered materials. PACS. 71.27.+a -Strongly correlated electron systems; heavy fermions.Abstract. -Theoretical investigations of the electronic, magnetic and structural properties of LaTiO3 and YTiO3 have been made. In the framework of GGA and GGA+U scheme we analyzed the effect of the local Coulomb interaction (U ) value on the atomic forces acting in the experimental structure. The optimal parameters of the electron-electron on-site interactions as well as the orbital configurations and magnetic properties are determined.Introduction. -Transition-metal perovskite oxides LaTiO 3 and YTiO 3 are classical MottHubbard insulators. In spite of the fact that they are formally isoelectronic with one 3d electron in the t 2g shell LaTiO 3 has a G-type antiferromagnetic (AFM) structure whereas YTiO 3 has a ferromagnetic (FM) one. The most unusual feature of these compounds relates with a nearly isotropic magnon spectrum in both titanates despite of their distorted crystal structures [1,2].There are two theoretical models aimed to explain these effects in LaTiO 3 . One of them originates from the work of Kugel and Khomskii [3] and operates in terms of the lattice distortions and an orbital ordering (OO). Another one is proposed by Khalliulin and Maekawa [4] and describes the above effects by the model of orbital liquid (OL) where the fluctuations of orbital degrees of freedom play an important role. According to [4] the energy of the orbital fluctuations is estimated to be W orb ∼ 160 meV. Thus OL model is applicable only if the splitting of the t 2g orbital in the crystal field ∆ is significantly smaller than W orb . Otherwise the nearly isotropic exchange is likely to be due to an orbital ordering with a peculiar orbital configuration [9].The OL model was supported by neutron experiments of Keimer et al [1] where no OO in LaTiO 3 was found. Fritsch with co-workers [5] made heat capacity and magnetic measurements. Having supposed the nearly cubic structure of LaTiO 3 they concluded that the energy of the spin-orbit coupling for Ti-sites was E SO = 30 meV and the crystal field effect was small. The theoretical estimations made by Solovyev in Ref. [6] in the framework of the local spin density approximation (LSDA) and LSDA+U theory showed that ∆ in LaTiO 3 was as small

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