اشترك بالحزمة الذهبية واحصل على وصول غير محدود شمرا أكاديميا
تسجيل مستخدم جديدCorrelation Between Phase Competition and the Nucleation of a Griffiths Phase in (La1-yPry)0.7Ca0.3Mn16/18O3
110
0
0.0
(
0
)
اسأل ChatGPT حول البحث
ﻻ يوجد ملخص باللغة العربية
Detailed analyses of the temperature-dependent zero field ac susceptibility of prototypical phase-separated (La1-yPry)0.7Ca0.3Mn16/18O3, 0 < y < 1, reveal features consistent with the presence of a Griffiths phase (GP), viz., an inverse susceptibility characterized by power law with 0.05 < lamda < 0.33 as y decreases towards yc < 0.85. Beyond yc = 0.85, the GP is suppressed. These data, combined with previous neutron diffraction measurements, enable a phase diagram summarizing the evolution of the GP with composition to be constructed for this system; in particular, it shows that the disorder relevant for the establishment of such a phase is linked closely to the relative volume fractions of the phase separated antiferromagnetic and ferromagnetic components, even when the recently estimated double exchange (DE) linked percolation threshold is exceeded. The influence of electron-phonon coupling can also be seen through oxygen isotope effects.
قيم البحث
اقرأ أيضاً
We report on the discovery of a novel triangular phase regime in the system La1-xSrxMnO3 by means of electron spin resonance and magnetic susceptibility measurements. This phase is characterized by the coexistence of ferromagnetic entities within the
globally paramagnetic phase far above the magnetic ordering temperature. The nature of this phase can be understood in terms of Griffiths singularities arising due to the presence of correlated quenched disorder in the orthorhombic phase.
Critical points that can be suppressed to zero temperature are interesting because quantum fluctuations have been shown to dramatically alter electron gas properties. Here, the metal formed by Co doping the paramagnetic insulator FeS$_2$, Fe$_{1-x}$C
o$_x$S$_2$, is demonstrated to order ferromagnetically at $x>x_c=0.01pm0.005$ where we observe unusual transport, magnetic, and thermodynamic properties. We show that this magnetic semiconductor undergoes a percolative magnetic transition with distinct similarities to the Griffiths phase, including singular behavior at $x_c$ and zero temperature.
Magnetic topological phases of quantum matter are an emerging frontier in physics and material science. Along these lines, several kagome magnets have appeared as the most promising platforms. However, the magnetic nature of these materials in the pr
esence of topological state remains an unsolved issue. Here, we explore magnetic correlations in the kagome magnet Co_3Sn_2S_2. Using muon spin-rotation, we present evidence for competing magnetic orders in the kagome lattice of this compound. Our results show that while the sample exhibits an out-of-plane ferromagnetic ground state, an in-plane antiferromagnetic state appears at temperatures above 90 K, eventually attaining a volume fraction of 80% around 170 K, before reaching a non-magnetic state. Strikingly, the reduction of the anomalous Hall conductivity above 90 K linearly follows the disappearance of the volume fraction of the ferromagnetic state. We further show that the competition of these magnetic phases is tunable through applying either an external magnetic field or hydrostatic pressure. Our results taken together suggest the thermal and quantum tuning of Berry curvature field via external tuning of magnetic order. Our study shows that Co_3Sn_2S_2 is a rare example where the magnetic competition drives the thermodynamic evolution of the Berry curvature field, thus tuning its topological state.
A systematic x-ray magnetic circular dichroism study of the paramagnetic phase of ErCo2 has recently allowed to identify the inversion of the net magnetization of the Co net moment with respect to the applied field well above the ferrimagnetic orderi
ng temperature, Tc. The study of small angle neutron scattering measurements has also shown the presence of short range order correlations in the same temperature region. This phenomenon, which we have denoted parimagnetism, may be related with the onset of a Griffiths-like phase in paramagnetic ErCo2. We have measured ac susceptibility on ErCo2 as a function of temperature, applied field, and excitation frequency. Several characteristics shared by systems showing a Griffiths phase are present in ErCo2, namely the formation of ferromagnetic clusters in the disordered phase, the loss of analyticity of the magnetic susceptibility and its extreme sensitivity to an applied magnetic field. The paramagnetic susceptibility allows to establish that the magnetic clusters are only formed by Co moments as well as the intrinsic nature of those Co moments.
The structural and magnetic properties of double perovskiteTb2CoMnO6 have been investigated. Electronic structure analysis by XPS study reveals the presence of mixed oxidation state (Mn4+/Mn3+ and Co2+/Co3+) of B-site ions. The dc and ac magnetizatio
n measurements reveal different interesting phases such as Griffith phase, re-entrant spin glass, metamagnetic steps, Hopkinson like peak and also unusual slow relaxation. The M-H curve indicates the presence of competing AFM/FM interactions. The disorder in Tb2CoMnO6 leads to spin frustration at low temperature giving rise to the re-entrant spin glass. Moreover, the field-dependent ac susceptibility studies unraveled the presence of Hopkinson like peak associated with the domain wall motion and the large anisotropy field. The further study yielded that the relaxation associated with this peak is unusually slow.
سجل دخول لتتمكن من نشر تعليقات
التعليقات
جاري جلب التعليقات
سجل دخول لتتمكن من متابعة معايير البحث التي قمت باختيارها
