Antiferromagnetic ordering and dipolar interactions of YbAlO3_3

In this paper we report low-temperature magnetic properties of the rare-earth perovskite material YbAlO$_3$. Results of elastic and inelastic neutron scattering experiment, magnetization measurements along with the crystalline electrical field (CEF) calculations suggest that the ground state of Yb moments is a strongly anisotropic Kramers doublet, and the moments are confined in the $ab$-plane, pointing at an angle of $\varphi = \pm 23.5^{\circ}$ to the $a$-axis. With temperature decreasing below $T_{\rm N}=0.88$ K, Yb moments order into the coplanar, but non-collinear antiferromagnetic (AFM) structure $AxGy$, where the moments are pointed along their easy-axes. In addition, we highlight the importance of the dipole-dipole interaction, which selects the type of magnetic ordering and may be crucial for understanding magnetic properties of other rare-earth orthorhombic perovskites. Further analysis of the broad diffuse neutron scattering shows that one-dimensional interaction along the $c$-axis is dominant, and suggests YbAlO$_3$ as a new member of one dimensional quantum magnets.Comment: 8 pages, 6 figure

Multiple fermion scattering in the weakly coupled spin-chain compound YbAlO3

The Heisenberg antiferromagnetic spin-1/2 chain, originally introduced almost a century ago, is one of the best studied models in quantum mechanics due to its exact solution, but nevertheless it continues to present new discoveries. Its low-energy physics is described by the Tomonaga-Luttinger liquid of spinless fermions, similar to the conduction electrons in one-dimensional metals. In this work we investigate the Heisenberg spin-chain compound YbAlO3 and show that the weak interchain coupling causes Umklapp scattering between the left- and right-moving fermions and stabilizes an incommensurate spin-density wave order at q = 2kF under finite magnetic fields. These Umklapp processes open a route to multiple coherent scattering of fermions, which results in the formation of satellites at integer multiples of the incommensurate fundamental wavevector Q = nq. Our work provides surprising and profound insight into bandstructure control for emergent fermions in quantum materials, and shows how neutron diffraction can be applied to investigate the phenomenon of coherent multiple scattering in metals through the proxy of quantum magnetic systems

Multiple fermion scattering in the weakly coupled spin-chain compound YbAlO3

The Heisenberg antiferromagnetic spin-1/2 chain, originally introduced almost a century ago, is one of the best studied models in quantum mechanics due to its exact solution, but nevertheless it continues to present new discoveries. Its low-energy physics is described by the Tomonaga-Luttinger liquid of spinless fermions, similar to the conduction electrons in one-dimensional metals. In this work we investigate the Heisenberg spin-chain compound YbAlO3 and show that the weak interchain coupling causes Umklapp scattering between the left- and right-moving fermions and stabilizes an incommensurate spin-density wave order at q = 2kF under finite magnetic fields. These Umklapp processes open a route to multiple coherent scattering of fermions, which results in the formation of satellites at integer multiples of the incommensurate fundamental wavevector Q = nq. Our work provides surprising and profound insight into bandstructure control for emergent fermions in quantum materials, and shows how neutron diffraction can be applied to investigate the phenomenon of coherent multiple scattering in metals through the proxy of quantum magnetic systems

Multiple fermion scattering in the weakly coupled spin-chain compound YbAlO3

The Heisenberg antiferromagnetic spin-1/2 chain, originally introduced almost a century ago, is one of the best studied models in quantum mechanics due to its exact solution, but nevertheless it continues to present new discoveries. Its low-energy physics is described by the Tomonaga-Luttinger liquid of spinless fermions, similar to the conduction electrons in one-dimensional metals. In this work we investigate the Heisenberg spin-chain compound YbAlO3 and show that the weak interchain coupling causes Umklapp scattering between the left- and right-moving fermions and stabilizes an incommensurate spin-density wave order at q = 2kF under finite magnetic fields. These Umklapp processes open a route to multiple coherent scattering of fermions, which results in the formation of satellites at integer multiples of the incommensurate fundamental wavevector Q = nq. Our work provides surprising and profound insight into bandstructure control for emergent fermions in quantum materials, and shows how neutron diffraction can be applied to investigate the phenomenon of coherent multiple scattering in metals through the proxy of quantum magnetic systems

DAMPAK WISATAWAN ASING TERHADAP PERUBAHAN SOSIAL BUDAYA MASYARAKAT (STUDI PADA MASYARAKAT DI KEC. LHOKNGA KAB. ACEH BESAR)

ABSTRAKBerkembangnya pariwisata di tengah masyarakat membawa pengaruh terhadap kehidupan sosial budaya. Pariwisata selalu mempertemukan dua atau lebih kebudayaan yang akan menghasilkan berbagai proses perubahan seperti akulturasi, dominasi, asimilasi, adopsi, adaptasi dan sebagainya. Wisatawan mancanegara yang berkunjung ke Lhoknga telah membawa pengaruh terhadap masyarakat lokal di daerah sekitar objek wisata. Penelitian ini bertujuan untuk mengetahui dampak pariwisata terhadap perubahan sosial budaya masyarakat dan mengetahui bentuk perubahan sosial budaya yang terjadi pada masyarakat Lhoknga akibat perkembangan pariwisata di Mukim Lhoknga. Metodologi penelitian ini menggunakan pendekatan kualitatif dengan model studi deskriptif. Pengumpulan data dilakukan dengan wawancara mendalam dan observasi. Dari hasil penelitian menunjukkan bahwa terjadinya perubahan sosial budaya pada masyarakat lokal di Mukim Lhoknga, Kecamatan Lhoknga Kabupaten Aceh Besar. Namun perubahan yang dimaksud masih dikategorikan perubahan secara mikro, karena tidak membawa pengaruh yang mendalam pada kehidupan masyarakat lokal. Dampak pariwisata terhadap perubahan sosial budaya masyarakat dapat dipilah menjadi dua yaitu dampak positif dan dampak negatif. Dampak positifnya yaitu dengan adanya pariwisata telah membuka lapangan kerja baru bagi masyarakat lokal yang dapat meningkatkan pendapatan ekonomi, mampu menguasai bahasa asing, seperti bahasa Inggris, Jepang. Terbukanya akses bagi masyarakat lokal ke jaringan yang lebih luas, memperlihatkan keindahan alam dan budaya yang tak lepas dari rasa untuk meningkatkan persaudaraan dalam lingkungan nasional dan internasional Sedangkan dampak negatif yaitu, lunturnya budaya lokal (tradisional) akibat masuknya budaya luar (modern). Adapun bentuk-bentuk perubahan dapat dilihat dari dua segi yaitu perubahan segi sosial dan perubahan dari segi budaya. Bentuk perubahan dari segi sosial yaitu terjadinya perubahan struktur sosial masyarakat lokal dengan beralihnya sektor pekerjaan dari petani atau nelayan ke sektor industri, Meningkatnya keinginan untuk berpendidikan tinggi, sedangkan perubahan dari segi budaya yaitu terjadinya perkawinan dari dua unsur budaya yang berbeda, perubahan pada penggunaan bahasa, perubahan cara berpakaian dan perubahan perilaku dalam keluarga.Kata Kunci : Pariwisata, Wisatawan Asing, Perubahan Sosial, Perubahan Budaya.Banda Ace

Використання сульфід- та тіосульфат-іонів пурпуровими несірковими бактеріями Rhodopseudomonas yavorovii

This article covers the patterns of oxidation of sulfide and thiosulfate ions by bacteria Rhodopseudomonas yavorovii Ya-2016 under different cultivation conditions. In the environments with 1.4–5.6 мМ Na2S2O3, R. yavorovii Ya-2016 bacteria accumulated biomass of 1.4–1.6 g/l, which was higher than biomass (1.2-0.6 g/l) accumulated by the bacteria with the same concentrations of Na2S × 9H2O. The efficiency of oxidation of 1.4, 2.8, 5.6 мМ sulfide- and thiosulfate-ions as donors of electrons by the bacteria equaled 97.4, 42.6, 18.7 and 68.8, 28.0, 3.7%, respectively. As a result of bacterial oxidation of 1.4 мМ hydrogen sulfide and sodium thiosulphate in the environment accumulation of 0.13–1.30 мМ sulfate-ions occurs, and the element sulfur becomes an intermediate metabolite in the environment with Na2S×9H2O. R. yavorovii Ya-2016 bacteria are capable of using sulfate-ions as a single source of sulfate at increase in photptrophs. In the environment with 2.5 мМ sulfate-ions concentration the bacteria biomass was 1.4 g/l, the bacteria assimilated 17.7% of sulfates. Because purple non-sulfur bacteria R. yavorovii Ya-2016 are capable of using sulfide-ions as donors of electrons of anoxygenic photosynthesis and using sulfate-ions as a single source of sulfate, they could be successfully used in the technologies of remediating the environment from compounds of sulfur. Охарактеризовано закономірності окиснення сульфід- та тіосульфат-іонів фототрофними пурпуровими несірковими бактеріями RhodopseudomonasyavoroviiYa-2016. У середовищах з 1,4–5,6 мМ Na2S2O3 бактерії R. yavoroviiYa-2016 нагромаджували біомасу 1,4–1,6 г/л, яка перевищувала біомасу (1,2–0,6 г/л), нагромаджену бактеріями з аналогічними концентраціями Na2S× 9H2O. Ефективність окиснення 1,4, 2,8, 5,6 мМ сульфід- та тіосульфат-іонів як донорів електронів бактеріями становила 97,4, 42,6, 18,7 та 68,8, 28,0, 3,7%, відповідно. В результаті окиснення бактеріями 1,4 мМ гідроген сульфіду та натрій тіосульфату у середовищі нагромаджується 0,13–1,30 мМ сульфат-іонів, а елементна сірка – проміжний метаболіт у середовищі з Na2S× 9H2O. R. yavoroviiYa-2016 здатні використовувати сульфат-іони як єдине джерело сульфуру за фототрофного росту. За концентрації 2,5 мМ сульфат-іонів у середовищі біомаса бактерій була 1,4 г/л, бактерії асимілювали 17,7% сульфатів. Оскільки пурпурові несіркові бактерії R. yavoroviiYa-2016 здатні використовувати сульфід-іони як донори електронів аноксигенного фотосинтезу та сульфат-іони як єдине джерело сульфуру, вони можуть бути успішно використані у технологіях ремедіації довкілля від сполук сульфуру.

Tomonaga-Luttinger Liquid Behavior and Spinon Confinement in YbAlO3_3

Low dimensional quantum magnets are interesting because of the emerging collective behavior arising from strong quantum fluctuations. The one-dimensional (1D) S = 1/2 Heisenberg antiferromagnet is a paradigmatic example, whose low-energy excitations, known as spinons, carry fractional spin S = 1/2. These fractional modes can be reconfined by the application of a staggered magnetic field. Even though considerable progress has been made in the theoretical understanding of such magnets, experimental realizations of this low-dimensional physics are relatively rare. This is particularly true for rare-earth based magnets because of the large effective spin anisotropy induced by the combination of strong spin-orbit coupling and crystal field splitting. Here, we demonstrate that the rare-earth perovskite YbAlO$_3$ provides a realization of a quantum spin S = 1/2 chain material exhibiting both quantum critical Tomonaga-Luttinger liquid behavior and spinon confinement-deconfinement transitions in different regions of magnetic field-temperature phase diagram.Comment: Main text: 25 pages, 7 figures; Supplementary Information: 11 pages, 8 figure

Multiple fermion scattering in the weakly coupled spin chain compound YbAlO3

The Heisenberg antiferromagnetic spin 1 2 chain, originally introduced almost a century ago, is one of the best studied models in quantum mechanics due to its exact solution, but nevertheless it continues to present new discoveries. Its low energy physics is described by the Tomonaga Luttinger liquid of spinless fermions, similar to the conduction electrons in one dimensional metals. In this work we investigate the Heisenberg spin chain compound YbAlO3 and show that the weak interchain coupling causes Umklapp scattering between the left and right moving fermions and stabilizes an incommensurate spin density wave order at q amp; 8201; amp; 8201;2kF under finite magnetic fields. These Umklapp processes open a route to multiple coherent scattering of fermions, which results in the formation of satellites at integer multiples of the incommensurate fundamental wavevector Q amp; 8201; amp; 8201;nq. Our work provides surprising and profound insight into bandstructure control for emergent fermions in quantum materials, and shows how neutron diffraction can be applied to investigate the phenomenon of coherent multiple scattering in metals through the proxy of quantum magnetic system

T2 Mapping from Super-Resolution-Reconstructed Clinical Fast Spin Echo Magnetic Resonance Acquisitions

Relaxometry studies in preterm and at-term newborns have provided insight into brain microstructure, thus opening new avenues for studying normal brain development and supporting diagnosis in equivocal neurological situations. However, such quantitative techniques require long acquisition times and therefore cannot be straightforwardly translated to in utero brain developmental studies. In clinical fetal brain magnetic resonance imaging routine, 2D low-resolution T2-weighted fast spin echo sequences are used to minimize the effects of unpredictable fetal motion during acquisition. As super-resolution techniques make it possible to reconstruct a 3D high-resolution volume of the fetal brain from clinical low-resolution images, their combination with quantitative acquisition schemes could provide fast and accurate T2 measurements. In this context, the present work demonstrates the feasibility of using super-resolution reconstruction from conventional T2-weighted fast spin echo sequences for 3D isotropic T2 mapping. A quantitative magnetic resonance phantom was imaged using a clinical T2-weighted fast spin echo sequence at variable echo time to allow for super-resolution reconstruction at every echo time and subsequent T2 mapping of samples whose relaxometric properties are close to those of fetal brain tissue. We demonstrate that this approach is highly repeatable, accurate and robust when using six echo times (total acquisition time under 9 minutes) as compared to gold-standard single-echo spin echo sequences (several hours for one single 2D slice)