Canonical and Non-Canonical Ising Spin Glass on Randomly Rewired Regular Lattices

Submitted for International Conference: CCP2016 IUPAP Conference on Computational Physics, 10-14 July 2016 Pretoria, South AfricaSpin glass (SG) has been an active research field in theoretical and experimental condensed matter physics in the last four decades. It is a random magnetic system mainly characterized by a frozen spin orientation at low temperatures. Frustration and randomness are considered to be the key ingredients for a system to exhibit SG behavior. The so-called non-\ud canonical SG is a new type of SG???s where frustration and randomness are different from that of\ud the canonical one where both ferromagnetic (FM) and antiferromagnetic (AF) couplings exist.\ud It is a purely AF system on structures with random connectivity and topological frustration.\ud The existence of this new type of SGs on various structures, such as scale free network, rewired\ud lattices and regular graphs for models such as Ising and Heisenberg spins has been reported\ud by several previous studies. Further elaboration of this system is required, in particular for a\ud comparison to the canonical type of each corresponding model such as Ising and Heisenberg\ud model on the same irregular structure. Here we study the Ising models on rewired regular\ud lattices of both canonical and non-canonical SG model. We used Replica Exchange of Monte\ud Carlo method and calculate the SG order parameter to search for SG phase. We estimate the critical temperature and exponents of the SG phase observed

STUDI PERUBAHAN FASE MODEL MAGNETIK SIMETRI POLIHEDRAL PADA KISI REGULER DAN KOMPLEKS

Studi perubahan fase (PF) merupakan salah satu kajian penting dalam fisika modern baik secara teoretik maupun eksperimen[1]. Hal ini disebabkan oleh kenyataan bahwa beberapa bahan memiliki sifat khusus dan bernilai tinggi jika berada dalam fase tertentu. Contoh paling lazim adalah bahan magnetik yang berada pada fase feromagnetik di bawah temperatur Curie. Fase magnetik adalah fase teratur yang merupakan realisasi dari gejala kerja-sama (cooperative phenomena) antara spin-spin (momen magnetik) yang sukses mengatasi fluktuasi termal[2]. Bahan magnet memiliki aplikasi sangat luas, dari storage, saklar, sensor, recorder magnetik, hingga komponen utama pembangkit listrik. \ud \ud Penemu-kenalan keberadaan PF dan sifat-sifatnya merupakan topik penting yang perlu dikaji. PF terjadi akibat adanya kompetisi antara sifat internal bahan (dinyatakan dalam tetapan gandeng) dan fluktuasi termal. Untuk bahan magnetik yang mengalami PF kontinu (orde kedua), karakteristik bahan di sekitar titik kritis ditentukan oleh sejumlah parameter kritis. Perolehan parameter kritis secara teoretik dan eksperimen sangat penting sebab memiliki sifat universalitas dimana sistem fisis berbeda dapat memiliki nilai kritis yang sama. Parameter kritis memuat informasi skenario kerusakan simetri dari sistem; dimana nilainya secara umum bergantung pada dimensi ruang, tetapan gandeng dan sifat simetri spin. Penemu-kenalan sifat kritis model-model magnetik berperan penting dalam pengembangan material baru dengan unjuk kerja (performance) handal

Spin glass behavior of the antiferromagnetic Heisenberg model on scale free network

Hasanuddin UniversityThe study of spin glasses (SG???s) has been an active research field for the last three\ud decades. The importance of the systems lies in the fact that they have some significance not\ud only for other parts of physics, but also for such fields as computer science, mathematics and\ud biology, including many technological applications. They are a class of random magnets with\ud rich physical properties, such as infinite number of ground states, memory effect and aging\ud phenomena. Random frustration is considered to be the key ingredient for the existence of SG\ud behavior. It is realized by the presence of both ferromagnetic (FM) and antiferromagnetic\ud (AF) interactions in regular lattices. We previously observed spin glass behaviour of the\ud antiferromagnetic Ising model on scale free network (SFN)[1]. It is a new type of spin glass\ud systems, different from the canonical ones which requires random distribution of ferromagnetic\ud and antiferromagnetic interactions. Here we study spin glass behavior of Heisenberg spin models\ud with AF interaction on SFN. The canonical spin glass Heisenberg model is not observed in the d-\ud dimensional regular lattices for (d ?? 3)[2]. We can make an analogy for the connectivity density\ud C of SFN with the dimensionality of the regular lattice. It should be plausible to find the critical\ud value of C for the existence of SG behaviour, analogous to the lower critical dimension (dl) for\ud the canonical SG systems. We used Replica Exchange algorithm of Monte Carlo Method and\ud calculated the SG order parameter. We observed low temperature SG behavior and estimated\ud the critical temperature and exponents.\ud Reference

Diagram Fase Sistem Spin Ising Antiferomagnet Pada Jaringan Kompleks

Diagram fase dari sistem spin Ising antiferomagnet pada jaringan bebas skala yang rapat konektivitasnya bervariasi ditelaah dengan menggunakan metoda Monte Carlo algoritma pertukaran replika. Besaran fisis yang dihitung meliputi parameter pertindihan dan parameter Binder, keduanya bergantung pada temperatur. Jumlah simpul dalam jaringan bervariasi. Dengan menggunakan penyekalaan ukuran berhingga, temperatur peralihan fase untuk masing-masing rapat konektivitas dapat ditentukan, dan selanjutnya digambarkan diagram fasenya. Hasil yang diperoleh menunjukkan bahwa hingga rapat konektivitas tertentu, fase gelas spin kuat akan tetapi melemah pada keadaan konektivitas yang mendekati batas medan rerata, yaitu sistem kisi terkoneksi sempurna

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Paper for International ConferenceSpin glasses (SG's) have been actively studied in condensed matter physics in the last three decades. The importance of the systems lies in the fact that they have some significance not only for other parts of physics, but also for such fields as computer science, mathematics and biology, including some technological applications. They are a class of random magnets with rich physical properties, such as infinite number of ground states, memory effect and aging phenomena. Random frustration is the key ingredient for the existence of SG behavior, which can be realized either by the competition of ferromagnetic (FM) and antiferromagnetic (AF) couplings or by the topological factors such an irregular connectivity in complex networks. In this study we consider spin glass model of polyhedral spins with FM and AF couplings. We observed low temperature SG behavior and estimates the critical temperature and exponents

Search for the Heisenberg spin glass on rewired square lattices with antiferromagnetic interaction

Spin glass (SG) is a typical magnetic system with frozen random spin\ud orientation at low temperatures. The system exhibits rich physical properties,\ud such as infinite number of ground states, memory effect and aging phenomena. There are two main\ud ingredients considered to be pivotal for the existence of SG behavior,\ud namely, frustration and randomness. For the canonical SG system,\ud frustration is led by the presence of competing interaction between\ud ferromagnetic (FM) and antiferromagnetic (AF) couplings. Previously,\ud Bartolozzi {\it et al.} [ Phys. Rev. B{\bf 73}, 224419 (2006)],\ud reported the SG properties of the AF Ising spins on scale free network (SFN).\ud It is a new type of SG, different from the canonical\ud one which requires the presence of both FM and AF couplings.\ud In this new system, frustration is purely caused by the topological\ud factor and its randomness is related to the irregular connectvity.\ud Recently, Surungan {\it et. al.} reported SG bahavior of AF Heisenberg\ud model on SFN. We further investigate this type of system\ud by studying an AF Heisenberg model on rewired square lattices.\ud We used Replica Exchange algorithm of Monte Carlo Method and\ud calculated the SG order parameter to search for the existence of\ud SG phase