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Continuously Varying Critical Exponents Beyond Weak Universality.

ABSTRACT: Renormalization group theory does not restrict the form of continuous variation of critical exponents which occurs in presence of a marginal operator. However, the continuous variation of critical exponents, observed in different contexts, usually follows a weak universality scenario where some of the exponents (e.g., ?, ?, ?) vary keeping others (e.g., ?, ?) fixed. Here we report ferromagnetic phase transition in (Sm_1-yNd_y)_0.52Sr_0.48MnO₃ (0.5???y???1) single crystals where all three exponents ?, ?, ? vary with Nd concentration y. Such a variation clearly violates both universality and weak universality hypothesis. We propose a new scaling theory that explains the present experimental results, reduces to the weak universality as a special case, and provides a generic route leading to continuous variation of critical exponents and multi-criticality.

SUBMITTER: Khan N

PROVIDER: S-EPMC5361157 | biostudies-literature | 2017 Mar

REPOSITORIES: biostudies-literature

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Continuously Varying Critical Exponents Beyond Weak Universality.

Khan N N Sarkar P P Midya A A Mandal P P Mohanty P K PK

Scientific reports 20170322

Renormalization group theory does not restrict the form of continuous variation of critical exponents which occurs in presence of a marginal operator. However, the continuous variation of critical exponents, observed in different contexts, usually follows a weak universality scenario where some of the exponents (e.g., β, γ, ν) vary keeping others (e.g., δ, η) fixed. Here we report ferromagnetic phase transition in (Sm1-yNdy)0.52Sr0.48MnO3 (0 ...[more]

PMID: 28327622

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