اشترك بالحزمة الذهبية واحصل على وصول غير محدود شمرا أكاديميا
تسجيل مستخدم جديدUnderstanding the $mu$SR spectra of MnSi without magnetic polarons
104
0
0.0
(
0
)
اسأل ChatGPT حول البحث
ﻻ يوجد ملخص باللغة العربية
Transverse-field muon-spin rotation ($mu$SR) experiments were performed on a single crystal sample of the non-centrosymmetric system MnSi. The observed angular dependence of the muon precession frequencies matches perfectly the one of the Mn-dipolar fields acting on the muons stopping at a 4a position of the crystallographic structure. The data provide a precise determination of the magnetic dipolar tensor. In addition, we have calculated the shape of the field distribution expected below the magnetic transition temperature $T_C$ at the 4a muon-site when no external magnetic field is applied. We show that this field distribution is consistent with the one reported by zero-field $mu$SR studies. Finally, we present ab initio calculations based on the density-functional theory which confirm the position of the muon stopping site inferred from transverse-field $mu$SR. In view of the presented evidence we conclude that the $mu$SR response of MnSi can be perfectly and fully understood without invoking a hypothetical magnetic polaron state.
قيم البحث
اقرأ أيضاً
We investigate the anisotropic nature of magnetocrystalline coupling between the crystallographic and skyrmion crystal (SKX) lattices in the chiral magnet MnSi by magnetic field-angle resolved resonant ultrasound spectroscopy. Abrupt changes are obse
rved in the elastic moduli and attenuation when the magnetic field is parallel to the [011] crystallographic direction. These observations are interpreted in a phenomenological Ginzburg-Landau theory that identifies switching of the SKX orientation to be the result of an anisotropic magnetocrystalline coupling potential. Our paper sheds new light on the nature of magnetocrystalline coupling potential relevant to future spintronic applications.
We investigated the magnetic phase of the perovskite CaCrO$_3$ by using the muon spin relaxation technique accompanied by susceptibility measurements. A thermal hysteresis loop is identified with a width of about 1 K at the transition temperature. Wi
thin the time scale of the muon lifetime, a static antiferromagnetic order is revealed with distinct multiple internal fields which are experienced in the muon interstitial sites below the phase-transition temperature, $T_N=90 K$. Above $T_N$, lattice deformations are indicated by transverse-field muon-spin rotation and relaxation suggesting a magneto-elastic mechanism.
We report the existence of Griffiths phase (GP) and its influence on critical phenomena in layered Sr$_2$IrO$_4$ ferromagnet (T$_C$ = 221.5 K). The power law behavior of inverse magentic susceptibility, 1/$chi$(T) with exponent $lambda = 0.18(2)$ con
firm the GP in the regime T$_C$ $<$ T $leq$ T$_G$ = 279.0(5) K. Moreover, the detailed critical analysis via modified Arrott plot method exhibits unrealistic critical exponents $beta$ = 0.77(1), $gamma$ = 1.59(2) and $delta = 3.06(4)$, in corroboration with magneto-caloric study. The abnormal exponent values have been viewed in context of ferromagnetic-Griffiths phase transition. The GP has been further analyzed using Bray model, which yields a reliable value of $beta$ = 0.19(2), belonging to the two-dimensional (2D) XYh$_4$ universality class with strong anisotropy present in Sr$_2$IrO$_4$. The present study proposes Bray model as a possible tool to investigate the critical behavior for Griffiths ferromagnets in place of conventional Arrott plot analysis. The possible origins of GP and its correlation with insulating nature of Sr$_2$IrO$_4$ have been discussed.
We present a detailed investigation of the temperature and depth dependence of the magnetic properties of 3D topological Kondo insulator SmB6 , in particular near its surface. We find that local magnetic field fluctuations detected in the bulk are su
ppressed rapidly with decreasing depths, disappearing almost completely at the surface. We attribute the magnetic excitations to spin excitons in bulk SmB6 , which produce local magnetic fields of about ~1.8 mT fluctuating on a time scale of ~60 ns. We find that the excitonic fluctuations are suppressed when approaching the surface on a length scale of 40-90 nm, accompanied by a small enhancement in static magnetic fields. We associate this length scale to the size of the excitonic state.
We investigate the effects of two electronic bands at the negative electronic compressibility (NEC) in a two-dimensional electron gas (2DEG). We use a simple homogeneous model with Coulombic interactions and first-order multi-band coupling to examine
the role of effective mass and relative permittivity in relation to the critical carrier density, where compressibility turns negative. We demonstrate that the population of a second band, along with the presence of inter-band coupling, can dramatically change the cross-over carrier density. Given the difficulty in determining and confirming multi-band electronic systems, this model provides a potential method for identifying multi-band electronic systems using precise bulk electronic properties measurements. To help illustrate this method, we apply our results to the observed NEC in the 2D electron gas at the interface of LaAlO$_3$/SrTiO$_3$ (LAO/STO) and determine that, for the known parameters of LAO/STO, the system is likely a realization of a two-band 2D electron gas. Furthermore, we provide general limits on the inter-band coupling with respect to the electronic band population.
سجل دخول لتتمكن من نشر تعليقات
التعليقات
جاري جلب التعليقات
سجل دخول لتتمكن من متابعة معايير البحث التي قمت باختيارها
