Linear dichroism (LD) in x -ray absorption, diffraction, transport and magnetization measurements on thin La 0.7 Sr 0.3 MnO 3 films grown on different substrates, allow identification of a peculiar interface effect, related just to the presence of the interface. We report the LD signature of preferential 3d-e g (3z 2 -r 2 ) occupation at the interface, suppressing the double exchange mechanism.This surface orbital reconstruction is opposite to that favored by residual strain and is independent of dipolar fields, the chemical nature of the substrate and the presence of capping layers.Interfaces between perovskite oxides display unexpected properties. The roles of chemistry, polarization and strain may be singled out by selective experiments, e.g.Ref.[11], where an engineered interface obtained by intercalating two LMO unit cells (u.c.) between the LSMO and the STO has been shown to recover the LSMO bulk properties even at room temperature. The role of strain on preferential orbital occupation in transition metal oxides has been widely studied [12]. The anisotropy of d-orbitals influences the electron correlation effects in an orbital direction-dependent manner, thus giving rise to the anisotropy of the electron-transfer and eventually destroying the DE order of unstrained half-metallic LSMO (Fig.1, center). The strain effect on orbital physics can be understood on the basis of the experimental phase diagram proposedby Konishi et al.,[ 13] and explained theoretically by Fang et al.[14]. Spin ordering in strained manganite is influenced by orbital ordering and several anti-ferromagnetic (AF) insulating JahnTeller distorted phases are observed: the strain induced elongation or compression of the MnO 6 octahedra leads to crystal field splitting of the e g levels, lowering either i) the (3z 2 -r 2 ) state which favors the C -type AF structure (Fig.1, left) or ii) the (x 2 -y 2 ) state which stabilizes the A -type structure ( Fig.1, right resonant transition. Polarization effects arise when the polarization vector is set parallel to t he c crystallographic axis or perpendicular to it (I c and I ab respectively). The LD is the difference between the two spectra (I ab -I c ) and gives a direct insight of the empty Mn 3dstates: a LD which is on average positive (negative) indicates a majority o f off-plane (in-plane) empty 3d states. Considering the crystal field splitting, the effect can be mainly related to the occupation of the two e g states (3r 2 -z 2 and x 2 -y 2 ) with majority spin: a LD which is on average positive (negative) is due to a preferential occupation of the in-plane x 2 -y 2 (out-of-plane 3r 2 -z 2 )orbital.Magnetization measurements were carried out by a SQUID magnetometer. Further experimental details are given in ref.[16] and [26].In Fig.2 Fig.4(b), revealing opposite signs for these two cases.Although the comparison with experiments can only be qualitative and a proper fit is not feasible, the sign reversal is observed in the experimental spectra of Fig.4(a) for energies above the E˜644 ...

We performed zero and transverse field µSR experiments on a large number of YBa2Cu3O6+x samples. We detect coexistence of antiferro-type (AF) short range magnetism with superconductivity below T f 10 K in compositions 0.37 x 0.39. Most muons experience local AF fields, even when SQUID detects a full superconducting volume fraction, which points to a local minimal interference organization of short AF stripes embedded in the superconductor. A detailed phase diagram is produced and the consequences of the minimal interference are discussed. Neutron scattering also detects magnetic correlations, notably [10] in YBa 2 Cu 3 O 6.35 , exclusively dynamic in nature, although their static counterpart could be elusive due to a very short correlation length. The doubled magnetic unit cell indicates an antiferromagnetic (AF) structure, with a suggested stripe-like character.In all the samples explored so far by µSR [5,6,7,8,9] it has been hinted that the cluster spin glass nature of magnetism (low spin freezing temperature, T f , large distributions of B i and absence of long range order as from neutron diffraction [11,12]) might be favored by the disorder inherent in cation substituted perovskites, which directly influences the CuO 2 layers. Conversely in YBa 2 Cu 3 O 6+x (123, hereafter) the source of disorder, namely the basal CuO x layers, are farther removed from the CuO 2 layers, but systematic µSR data were lacking, prior to the present work. Our aim is to clarify whether the appearance of coexisting superconducting and magnetic properties is indeed intrinsic to the unperturbed underdoped CuO 2 layers and whether the two properties cooperate or interfere.We performed µSR measurements on twenty-four polycrystalline 123 samples (Y 1−24 ) prepared by the topotactic technique, which consists of oxygen equilibration of stoichiometric quantities of the two end member specimens, tightly packed in sealed vessels [13]. Low temperature annealing yields high quality homogeneous samples with an absolute error of δx=±0.02 in oxygen content per formula unit and a much smaller relative error between samples of the same batch. The width of the interval were the resistance drops from 90% to 10% of the onset value is 0.5 K at optimal doping and 6-7K at x 0.4 (vs. e.g. 10K in Ref.10). The hole content h was determined from the resistive T c for the superconducting samples [14], and from the Seebeck coefficient S at 290 K for the non-superconducting ones, using the exponential dependence [14] of S on h, with fit parameters determined from our series of samples [15]. Samples Y 1−8 , with oxygen content 0.20≤x≤0.32 and hole content per planar Cu atom 0.033≤h≤0.055, never superconduct, and their AF properties were reported previously [16]. Samples Y 9−24 , with 0.32≤x≤0.42 and 0.055≤h≤0.08, are superconductors and are the subject of the present work.The µSR experiment were performed on the MUSR spectrometer of the ISIS pulsed muon facility, where the external magnetic field H may be applied either parallel to the initial muon spin S µ , in...

We demonstrate that the [Yb(trensal)] molecule is a prototypical coupled electronic qubit-nuclear qudit system. The combination of noise-resilient nuclear degrees of freedom and large reduction of nutation time induced by electron-nuclear mixing enables coherent manipulation of this qudit by radio frequency pulses. Moreover, the multilevel structure of the qudit is exploited to encode and operate a qubit with embedded basic quantum error correction.

55 Mn NMR experiments were carried out at 1.3-4.2 K on six samples of lanthanum manganites, with a hole doping concentration ranging from the antiferromagnetic-insulator to the ferromagnetic-conductor region of the phase diagram. The dependence of the resonance frequencies on external fields is either as expected for ferromagnets ͑FM͒ or for antiferromagnets ͑AF͒. No indication of a canted phase could be detected. FM and AF resonances were found to coexist in all samples and are grouped in three broad bands, whose frequencies do not depend in first order on hole concentration. Strong evidence of interaction between AF and FM regions was provided by longitudinal relaxation experiments in several samples. An explanation of this behavior is offered in terms of intrinsic phase separation of the holes into FM microdomains. We determine the 55 Mn hyperfine coupling to be isotropic in all cases, with Aϭ6.2 T/ B for the on-site term in the AF domains.

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