We demonstrate that femtosecond laser pulses allow triggering high-frequency standing spin-wave modes in nanoscale thin films of a bismuth-substituted yttrium iron garnet. By varying the strength of ...the external magnetic field, we prove that two distinct branches of the dispersion relation are excited for all the modes. This is reflected in particular at a very weak magnetic field (∼33 mT) by a spin dynamics with a frequency up to 15 GHz, which is 15 times higher than the one associated with the ferromagnetic resonance mode. We argue that this phenomenon is triggered by ultrafast changes of the magnetic anisotropy via laser excitation of incoherent and coherent phonons. These findings open exciting prospects for ultrafast photo magnonics.
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The prevalence of cardiac cachexia has previously been estimated to 8–42 %. However, novel treatment strategies for chronic heart failure (CHF) have improved and decreased morbidity and mortality. ...Therefore, we aimed to reassess the prevalence of cachexia in an outpatient CHF clinic and to characterize a CHF population with and without cachexia with respect to body composition and related biomarkers. From 2008 to 2011, we screened 238 optimally treated, non-diabetic CHF patients for cardiac cachexia, defined as unintentional non-oedematous weight loss of >5 % over ≥6 months. CHF patients (LVEF <45 %) with cachexia (
n
= 19) and without (
n
= 19) were compared to controls with prior myocardial infarction and left ventricular ejection fraction (LVEF) >45 % (
n
= 19). The groups were matched for age, sex, and kidney function. Body composition was assessed by dual energy X-ray absorptiometry. The prevalence of cachexia was 10.5 %. Abdominal fat ± SD (%) was reduced in cachectic CHF: 27.4 ± 10.0 versus 37.5 ± 10.6 % (CHF, no cachexia) and 40.6 ± 8.0 % (controls), (
P
< 0.001). NT-proBNP levels were inversely correlated to abdominal fat in a multivariate linear regression analysis adjusted for known predictors of NT-proBNP (LVEF and NYHA); (
β
= −0.28;
P
= 0.018). Myostatin levels were reduced in cachectic CHF compared to controls (
P
= 0.013). The prevalence of cachexia in stable CHF, treated according to recent guidelines, is lower than previously anticipated. Body alterations in cachexia consist mainly of reduced abdominal fat mass, and its inverse correlation to NT-proBNP suggests involvement of abdominal lipolysis. Our data do not support a role of circulating myostatin as a biomarker for muscle wasting.
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EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
Outpatient follow-up in specialized heart failure clinics (HFCs) is recommended by current guidelines and implemented in most European countries, but the optimal duration of HFC programmes has not ...been established. Nor is it known whether all or only high-risk patients, e.g. identified by NT-proBNP, might benefit from an extended HFC follow-up.
In a multi-centre setting, we randomly assigned 921 clinically stable systolic heart failure (HF) outpatients on optimal medical therapy to undergo either an extended follow-up in the HFC (n = 461) or referral back to their general practitioner (GP) (n = 460). The primary composite endpoint was death or a cardiovascular admission. Secondary endpoints included mortality, an HF admission, quality of life, number of days admitted, and number of admissions. The median age of the patients was 69 years; 23% were females; the median left ventricular ejection fraction was 0.30; and the median NT-proBNP was 801 pg/mL; 89% were in NYHA class I-II. The median follow-up was 2.5 years. Time-to-event did not differ between groups (HFC vs. GP) (HR: 1.17, 95% CI: 0.95-1.45, P = 0.149). The two groups did not differ with respect to any of the secondary endpoints at the follow-up (P> 0.05 for all). In high-risk patients identified by NT-proBNP ≥1000 pg/mL, no benefit from HFC follow-up was found (P = 0.721).
Irrespective of the level of NT-proBNP stable HF patients on optimal medical therapy do not benefit from long-term follow-up in a specialized HFC in a publicly funded universal access healthcare system. Heart failure patients on optimal medical therapy with mild or moderate symptoms are safely managed by their personal GP.
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We investigate spin-wave resonance modes and their damping in insulating thin films of bismuth-substituted yttrium iron garnet by performing femtosecond magneto-optical pump-probe experiments. For ...large magnetic fields in the range below the magnetization saturation, we find that the damping of high-order standing spin-wave (SSW) modes is about 40 times lower than that for the fundamental one. The observed phenomenon can be explained by considering different features of magnetic anisotropy and exchange fields that, respectively, define the precession frequency for fundamental and high-order SSWs. These results provide further insight into SSWs in iron garnets and may be exploited in many new photomagnonic devices.
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In this paper, we investigate the magnetic, optical, and lattice responses of a Pt/Cu/Bi1 Y2 Fe5 O12/Gd3 Ga5 O12 heterostructure to femtosecond laser excitation of the opaque Pt/Cu metallic bilayer. ...The electronic excitation generates coherent and incoherent phonons, which trigger high-frequency standing spin waves (SWs) in the dielectric Bi1 Y2 Fe5 O12 layer via a phonon-induced change of magnetic anisotropy. We find that the incoherent phonons (heat) can induce a fast (< 1 ps) and slow (> 1000 ps) decrease of the magnetic order by different spin-phonon interaction scenarios. These results open perspectives for generating high-frequency SWs in buried magnetic garnets.
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Ultrathin bismuth iron garnet Bi3Fe5O12 films were grown epitaxially on (001)-oriented gadolinium gallium garnet substrates. Film thickness varied from two to three dozens of unit cells. Bi3Fe5O12 ...films grow pseudomorphically on substrates up to a thickness of 20nm, and then a lattice relaxation occurs. Magnetic properties of the films were studied as a function of bismuth iron garnet thickness. The magnetization and cubic anisotropy decrease with decreasing film thickness. The uniaxial magnetocrystalline anisotropy is constant for all film thicknesses. For two unit cell thick films, the easy magnetization axis changes from in-plane to perpendicular to the plane direction. Such a reorientation takes place as a result of the competition of constant uniaxial perpendicular anisotropy with weakening film magnetization.
► Ultrathin Bi3Fe5O12 films were grown epitaxially on structure-matching substrates. ► Magnetic properties of Bi3Fe5O12 were studied down to the thickness of 2.5nm. ► Reorientation of easy magnetization axis as a function of film thickness was observed.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
SrVO3 (SVO) is a model system for strongly correlated oxides and is highly promising as conductive layer in heterostructures. Therefore, the control of electronic properties and morphology are ...essential for the advanced applications. Here, the oxygen stability during and after the deposition is explored, as SVO film is expected to undergo different postdeposition thermal and atmosphere treatments during its integration in a heterostructure. Hence, the influence of oxygen stability on morphology and electrical properties of the metallic SrVO3 grown by pulsed laser deposition has been investigated. Films grown under vacuum (SrVO3−
δ
) exhibit a very smooth surface while films grown under higher oxygen pressure roughen and present nanostructures at the surface. These nanostructures are found to be of Sr3V2O8 phase and their apparition can be controlled by the oxygen supply. Subsequent thermal treatments at different temperatures under same oxygen pressure prevent formation of the Sr3V2O8 phase, lead to the stoichiometric SrVO3, and thus improve the transport properties. In this study is shown the extreme sensitivity of SVO to oxygen and the conditions to obtain high quality smooth SVO films with improved electrical properties for electrode application.
Influence of oxygen onto the stability of SrVO3 film: At high temperature, these self‐organized nanostructures appear with an angle of 90° between the two variants in an oxidizing atmosphere. They have been identified as Sr3V2O8. A fine control of oxygen pressure and temperature prevent their formation in order to obtain smooth and good quality of SrVO3 thin films.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SBCE, SBMB, UL, UM, UPUK
Bismuth iron garnet Bi3Fe5O12 (BIG) is a multifunctional insulating oxide exhibiting remarkably the largest known Faraday rotation and linear magnetoelectric coupling. Enhancing the electrical ...conductivity in BIG while preserving its magnetic properties would further widen its range of potential applications in oxitronic devices. Here, a site‐selective codoping strategy in which Ca2+ and Y3+ substitute for Bi3+ is applied. The resulting p‐ and n‐type doped BIG films combine state‐of‐the‐art magneto‐optical properties and semiconducting behaviors above room temperature with rather low resistivity: 40 Ω cm at 450 K is achieved in an n‐type Y‐doped BIG; this is ten orders of magnitude lower than that of Y3Fe5O12. High‐resolution electron spectromicroscopy unveils the complete dopant solubility and the charge compensation mechanisms at the local scale in p‐ and n‐type systems. Oxygen vacancies as intrinsic donors play a key role in the conduction mechanisms of these doped BIG films. On the other hand, a self‐compensation of Ca2+ with oxygen vacancies tends to limit the conduction in p‐type Ca/Y‐doped BIG. These results highlight the possibility of integrating n‐type and p‐type doped BIG films in spintronic structures as well as their potential use in gas sensing applications.
Resistive changes in Y‐substituted bismuth iron garnet (BIG) can be fine‐tuned by three orders of magnitude under controlled atmosphere yielding n‐type semiconducting‐like resistivity as low as 103 Ω cm at room temperature. Electron spectromicroscopy techniques evidence additional (Fe2+) charge carriers in the low‐resistance state relative to the high‐resistance state. Oxygen vacancies act as intrinsic donors in these n‐type doped‐BIG thin films.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SBCE, SBMB, UL, UM, UPUK
In this paper we investigate the magneto-optical (MO) and magnetic properties of bismuth iron garnet Bi3Fe5O12 thin films over a wide range of photon energies (1.6–3.5 eV) and temperatures (5–740 K). ...Depending on the photon energy range, the Faraday rotation (ΘF) and ellipticity (ɛF) vary nonmonotonously with temperature. This behavior cannot be explained by a magnetization variation that can only decrease with increasing temperature. ΘF and ɛF spectra have therefore been analyzed using a model based on two optical transitions of a diamagnetic nature, representing the tetrahedral and octahedral iron sites. Thus, the contribution of each magnetic sublattice has been extracted from the global macroscopic MO response and investigated as a function of temperature. The magnetic properties of octahedral and tetrahedral sublattices depend differently on temperature, suggesting a different anisotropy due to oxygen coordination. We have demonstrated that this relatively simple macroscopic measurement with a subsequent analysis can grant access to the information on the properties at a microscopic level. These results can advance the fundamental understanding of MO properties in multisublattice magnetic materials.
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