Quantum Phase Transition from a Spin-liquid State to a Spin-glass State in the Quasi-1D Spin-1 System Sr1-xCaxNi2V2O8

We report a quantum phase transition from a spin-liquid state to a spin-glass state in the quasi-one dimensional (1D) spin-1 system Sr1-xCaxNi2V2O8, induced by a small amount of Ca-substitution at Sr site. The ground state of the parent compound (x = 0) is found to be a spin-liquid type with a finite energy gap of 26.6 K between singlet ground state and triplet excited state. Both dc-magnetization and ac-susceptibility studies on the highest Ca-substituted compound (x = 0.05) indicate a spin-glass type magnetic ground state. With increasing Ca-concentration, the spin-glass ordering temperature increases from 4.5 K (for the x = 0.015 compound) to 6.25 K (for the x = 0.05 compound). The observed results are discussed in the light of the earlier experimental reports and the theoretical predictions for a quasi-1D spin-1 system.Comment: 26 pages, 8 figures, 3 table

A Symbolic Interaction Analysis of Waria (Transgender Women) in Makassar - Eastern Indonesia

Transgender women (in Indonesia known as Waria) still experience social stigma and exclusion in society. This phenomenon is interesting to study because it is related to the existence of transgender women in dealing with stigma and social exclusion. This study aims to describe the way transgender women perceive social exclusion and to describe the construction of their knowledge which, despite facing social exclusion, still maintains their existence. This study used a qualitative-phenomenological study method, using a purposive sampling technique. Data collection was done by conducting observations, in-depth interviews, and documentation. Data were analyzed using qualitative descriptive using symbolic interaction theory. The results showed that transgender women perceive the stigma and social exclusion they faced was manifested by planned actions in the form of conditional neglect and delay in introducing their existence. They respond to social situations they face with adaptive and not frontal. Transgender women\u27s knowledge construction to maintain their existence is passed through four stages, namely impulse, perception, manipulation, and completion

Two-dimensional Induced Ferromagnetism

Magnetic properties of materials confined to nanometer length scales are providing important information regarding low dimensional physics. Using gadolinium based Langmuir-Blodgett films, we demonstrate that two-dimensional ferromagnetic order can be induced by applying magnetic field along the in-plane (perpendicular to growth) direction. Field dependent exchange coupling is evident in the in-plane magnetization data that exhibit absence of hysteresis loop and show reduction in field required to obtain saturation in measured moment with decreasing temperature.Comment: 4 pages, 3 postscript figures, corrected paper forma

Magnetocaloric effect and critical behavior near the paramagnetic to ferrimagnetic phase transition temperature in TbCo2-xFex

Magnetocaloric effect (MCE) in TbCo2-xFex has been studied by dc magnetization measurements.On substituting Fe in TbCo2, not only the magnetic transition temperature is tuned to room temperature, but also the operating temperature range for MCE is increased from 50 K for TbCo2 to 95 K for TbCo1.9Fe0.1. The maximum magnetic entropy change (-{\Delta}SM) for TbCo1.9Fe0.1 is found to be 3.7 J kg-1 K-1 for a 5 T field change, making it a promising candidate for magnetic refrigeration near room temperature. The temperature dependent neutron diffraction study shows a structural phase transition (from cubic to rhombohedral phase with lowering of temperature) which is associated with the magnetic phase transition and these transitions broaden on Fe substitution. To investigate the nature of the paramagnetic to ferrimagnetic phase transition, we performed a critical exponent study. From the derived values of critical exponents, we conclude that TbCo2 belongs to the 3D Heisenberg class with short-range interaction, while on Fe substitution it tends towards mean-field with long-range interaction. The derived values of critical exponents represent the phenomenological universal curve for the field dependence of {\Delta}SM, indicating that TbCo2 and TbCo1.9Fe0.1 belong to two different universality classes.Comment: 12 figure

Long-range and short-range magnetic correlations, and microscopic origin of net magnetization in the spin-1 trimer chain compound CaNi3P4O14

Spin-spin correlations and microscopic origin of net magnetization in the spin-1 trimer chain compound CaNi3P4O14 have been investigated by powder neutron diffraction. The present study reveals a 3D long-range magnetic ordering below 16 K where the magnetic structure consists of ferromagnetic trimers that are coupled ferromagnetically along the spin-chain. The moment components along the a and c axes arrange antiferromagnetically. Our study establishes that the uncompensated moment components along the b axis result in a net magnetization per unit cell. The magnetic structure, determined in the present study, is in agreement with the results of recent first principles calculation; however, it is in contrast to a fascinating experimental prediction of ferrimagnetic ordering based on the periodicity of the exchange interactions in CaNi3P4O14. Our study also confirms the presence of broad diffuse magnetic scattering, due to 1D short-range spin-spin correlations, over a wide temperature range below ~50 K down to a temperature well below the Tc. Total neutron scattering analysis by the RMC method reveals that the dominating spin-spin correlation above Tc is ferromagnetic and along the b axis. The nearest neighbour spin-spin correlations along the a and c axes are found to be weakly antiferromagnetic. The nature of the trimer spin structure of the short-range state is similar to that of the 3D long-range ordered state. The present investigation of microscopic nature of the magnetic ground state also explains the condition required for the 1/3 magnetization plateau to be observed in the trimer spin-chains. In spite of the S=1 trimer chain system, the present compound CaNi3P4O14 is found to be a good realization of 3D magnet below the Tc=16 K with full ordered moment values of ~2 mu_B/Ni2+ (1.98 and 1.96 mu_B/Ni2+ for two Ni sites, respectively) at 1.5 K.Comment: 10 pages, 8 figure

Enhanced grain surface effect on magnetic properties of nanometric La0.7Ca0.3MnO3 manganite : Evidence of surface spin freezing of manganite nanoparticles

We have investigated the effect of nanometric grain size on magnetic properties of single phase, nanocrystalline, granular La0.7Ca0.3MnO3 (LCMO) sample. We have considered core-shell structure of our LCMO nanoparticles, which can explain its magnetic properties. From the temperature dependence of field cooled (FC) and zero-field cooled (ZFC) dc magnetization (DCM), the magnetic properties could be distinguished into two regimes: a relatively high temperature regime T > 40 K where the broad maximum of ZFC curve (at T = Tmax) is associated with the blocking of core particle moments, whereas the sharp maximum (at T = TS) is related to the freezing of surface (shell) spins. The unusual shape of M (H) loop at T = 1.5 K, temperature dependent feature of coercive field and remanent magnetization give a strong support of surface spin freezing that are occurring at lower temperature regime (T < 40 K) in this LCMO nanoparticles. Additionally, waiting time (tw) dependence of ZFC relaxation measurements at T = 50 K show weak dependence of relaxation rate [S(t)] on tw and dM/dln(t) following a logarithmic variation on time. Both of these features strongly support the high temperature regime to be associated with the blocking of core moments. At T = 20 K, ZFC relaxation measurements indicates the existence of two different types of relaxation processes in the sample with S(t) attaining a maximum at the elapsed time very close to the wait time tw = 1000 sec, which is an unequivocal sign of glassy behavior. This age-dependent effect convincingly establish the surface spin freezing of our LCMO nanoparticles associated with a background of superparamagnetic (SPM) phase of core moments.Comment: 41 pages, 10 figure

Analisis RAPD ( Random Amplified Polymorphic DNA)untuk Diferensiasi Mycobacteriun tuberculosis isolat klinik sensitif INH dan Rifampisin di Makassar

This study aims to find out: (1) whether there is a genetic diversity on M.tuberculosis isolat clinic that is sensitif to INH dan rifampisin with RAPD method, and (2) the description of its polimorfism diferentiation. The research samples include 5 Mycobacteriun tuberculosis isolate that is sensitive to INH and rifampisin. The study includes DNA extraction using Wizard Genom DNA purification method, amplification using 5 primer: A-2 (5 TGCCGAGTCG 3 , 70% G+C ), OPN-09 ( 5TGCCGGCTTG 3, 70% G+C), N-9 (5 TGCCGGCTTG 3, 70% G+C), BG-66 (5CGACGCTGCG 3, 80% G+C) , 80% G+C), U-19 ( 5 GTCAGTGCGG 3, 70% G+C), and electroforesis. The isolat genetic diversity was analysed by using Dendro Unweighted Pair Group Method of Aritmethic (UPGMA) : A Dendogram Construction Utility method from Dr. Santi GarciaValive/2009. The results show that there is a genetic diversity on the 5 isolate Mycobacterium tuberculosis that are sensitive to INH and rifampisin, amplified with 5 primer. The size of amplified DNA bands is between 200-1100bp. The genetic variation can be seen in the number of fragments, the size of fragments and the number of polimorfik bands. The polimorfik percentage of the isolate is between 66.67% - 100%, or 80.28 in average. The UPGMA analysis results in a dendogram with a group cooficient of 0 40% or a diversity of 60 100%. Keywords: RAPD, Mycobacterium tuberculosis, sensitive to INH and rifampisin

The Role of Education in Preventing Honour-Based Abuse in England

Honour-based abuse (HBA) is a form of abuse that frequently remains undetected despite its pervasive nature and catastrophic effects. As an act of violence perpetrated predominantly against women and girls, HBA is the overarching term used for abuse inflicted upon victims because they have supposedly dishonoured their family and brought shame to their community. To date, there is a paucity of research that specifically explores the role of education in preventing HBA in England. In seeking to strengthen and advance knowledge in this area, this research aims to gain insights into the perspectives of key participants about the cross-cultural and contested nature of HBA, including the factors contributing to it, the ramifications for local and national policy, and the role of education in preventing HBA in the context of England. This thesis also illustrates how the insidious and invidious practices of HBA continue to be perpetuated toward the most vulnerable within society. Underpinned by a feminist theoretical framework, qualitative analysis was employed to explore how participants perceive how education may contribute to prevention of HBA. The research participants interviewed for this study, over a period of eight months, included four activists, three politicians, one Home Office senior civil servant, four academics, two Crown Prosecution Service (CPS) staff, and one senior police officer. The semi-structured interviews provided a comprehensive understanding of the significance and meaning that the research participants placed on the role of education in HBA, and HBA prevention. Thematic analysis was undertaken after the data was transcribed and input into NVivo to detect themes, identify codes, and define key themes and underlying subthemes. This analysis uncovered five key themes within this research inquiry. The first theme related to the definitions and practices of HBA and exploring participant perceptions of the elements that contribute to and influence HBA. The second theme identified the origins and perpetuations of HBA. In broad terms, this theme focused on the origins of the cultural practice, identified the trigger factors, and examined the impact of gender and patriarchy in relation to HBA. The third theme was in relation to identification and definition of perpetrators and victims. The fourth theme provided an overview of the positionality of the research participants including their backgrounds, roles, and responsibilities. The fifth theme explored solutions to HBA, including methods of eradication, taking into account interviewees’ views on how to address HBA, and the role of education and government organisations in preventing HBA. Whilst it was clear that steps have been taken by the State to address the phenomenon of HBA through community initiatives and statutory education, the impact of these initiatives on HBA was limited due to several factors, such as lack of effective training for teachers, community literacy in HBA, race relations within the migrant community, funding constraints, and the multiple viewpoints and experiences due to the intersectional nature of HBA. Weaving through the tapestry of migration, culture, discrimination, gender norms, and societal roles, this research generates new understandings on the role of education in preventing HBA in England by drawing on the views of key participants on policies and initiatives related to HBA