Relaxation of thermo-remanent magnetization in Fe-Cr GMR multilayers

The time decay of the thermo-remanent magnetization (TRM) in Fe-Cr giant magnetoresistive (GMR) multilayers has been investigated. The magnetization in these multilayers relaxes as a function of time after being cooled in a small magnetic field of 100 Oe to a low temperature and then the magnetic field is switched off. Low-field ($<$ 500 Oe) magnetization studies of these samples have shown hysteresis. This spin-glass-like behavior may originate from structural imperfections at the interfaces and in the bulk. We find that the magnetization relaxation is logarithmic. Here the magnetic viscosity is found to increase first with increasing temperature, then it reaches a maximum around T$_g$, and then it decreases with increasing temperature. This behavior is different from that of conventional spin glasses where the logarithmic creep rate is observed to increase with temperature. Power law also gives good fits and it is better than the logarithmic fit at higher temperatures. The dynamical effects of these multilayers are related to the relaxation of thermally blocked superparamagnetic grains and magnetic domains in the film layers.Comment: 19 page

Effective collective barrier for magnetic relaxation in frozen ferrofluids

Magnetic relaxation and frequency response were measured in frozen ferrimagnetic colloids of different concentrations. A crossover from reversible to irreversible behavior is observed for concentrated colloids. In irreversible state, magnetic relaxation is time-logarithmic over seven orders of magnitude of experimental time windows. A master curve construction within mean field phenomenological model is applied to extract effective collective barrier as a function of the irreversible magnetization. The barrier logarithmically diverges, providing evidence for self-organized critical behavior during magnetic relaxation in frozen ferrofluids

Engaging the Liminal: Indigenous Perceptions Within the Healthcare System

It is well documented that there is decreased access and utilization of healthcare services by minority populations. The purpose of this study was to explore experiences with, and views of, the healthcare system among remotely situated First Nations people of coastal British Columbia (BC), to shed light on elements considered crucial to healthcare delivery. The study was conducted as a critical ethnography with an underlying framework of phenomenology and critical social theory. Multiple sources of data collection included private interviews, community observations, conversations, celebratory gatherings, participant-observer field notes, and the art and music of the people involved. Multiphase data management consistent with immersion and crystallization offered reflective/emotional,structured and synthesis levels of analysis, providing a rich aggregate of themes. Findings revealed that individuals who had developed relationships of trust with providers, or whose family members acted as advocates in healthcare encounters reported a higher level of satisfaction with the healthcare they received. However, many voiced perceptions of prejudice and stigmatization, believing healthcare to be of a lower quality than that received by non-Aboriginal BC residents. These findings were deeply embedded contextually and were framed by the legacy of a colonial past, ongoing \u27civilized oppression,\u27 and the socioeconomics of isolated living

Magnetic relaxation in finite two-dimensional nanoparticle ensembles

We study the slow phase of thermally activated magnetic relaxation in finite two-dimensional ensembles of dipolar interacting ferromagnetic nanoparticles whose easy axes of magnetization are perpendicular to the distribution plane. We develop a method to numerically simulate the magnetic relaxation for the case that the smallest heights of the potential barriers between the equilibrium directions of the nanoparticle magnetic moments are much larger than the thermal energy. Within this framework, we analyze in detail the role that the correlations of the nanoparticle magnetic moments and the finite size of the nanoparticle ensemble play in magnetic relaxation.Comment: 21 pages, 4 figure

Experimentelle Untersuchungen von Wärmerohrsystemen für den Einsatz in elektrischen Arbeitskraftmaschinen

Gefördert im Rahmen des Projekts DEALBundesministerium für Wirtschaft und Klimaschutz. Grant Number: 0324326

Ruthenocuprates RuSr2(Eu,Ce)2Cu2O10: Intrinsic magnetic multilayers

We report ac susceptibility data on RuSr_2(Eu,Ce)_2Cu_2O_(10-y) (Ru-1222, Ce content x=0.5 and 1.0), RuSr_2GdCu_2O_8 (Ru-1212) and SrRuO_3. Both Ru-1222 (x=0.5, 1.0) sample types exhibit unexpected magnetic dynamics in low magnetic fields: logarithmic time relaxation, switching behavior, and `inverted' hysteresis loops. Neither Ru-1212 nor SrRuO_3 exhibit such magnetic dynamics. The results are interpreted as evidence of the complex magnetic order in Ru-1222. We propose a specific multilayer model to explain the data, and note that superconductivity in the ruthenocuprate is compatible with both the presence and absence of the magnetic dynamics.Comment: 9 pages, 11 figures, Revtex; submitted to Phys.Rev.

Experimental Investigation of the Multiphase Flow in Oil‐Injected Multiphase Twin Screw Pumps

Gefördert im Rahmen des Projekts DEA

Innovations in Theory Development for the Nursing Discipline Volume 1

For the final assignment in this class on theory development, I asked these creative nursing PhD students to either adapt or extend an existing midrange theory.The following papers represent great hope for the future of nursing knowledge, and we offer them as evidence to interested readers at any level who want to know why theory matters, how it relates to actual practice, and why the voices of reflective nurses at all levels of educational attainment are needed to advance our thinking and unfolding in the context of all health professions. Sincerely, Jennifer B. Averill, PhD, RN, Instructorhttps://digitalrepository.unm.edu/rural-cultural-health/1002/thumbnail.jp

Dimensions in Health : A Sample of Rural and Global Health Issues

We invite you to explore an array of issues touching culture, rurality, or both, in the following collection of essays. In this class, we have defined both culture and rurality broadly and in expansive contexts. Much remains to be done, both locally and globally, to improve the health status of our varied populations and residents. Please join us in the analysis and resolution of the health challenges, inequities, and noteworthy mysteries that characterize particular rural and cultural settings.https://digitalrepository.unm.edu/rural-cultural-health/1001/thumbnail.jp