English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Tools annual

Global: Zendy Free Plan

Global: Zendy Tools monthly

Global: Zendy Plus monthly

BaFe 12 O 19  is a popular M-type hexaferrite with a Néel temperature of 720 K and is of enormous commercial value ($3 billion/year). It is an incipient ferroelectric with an expected ferroelectric phase transition extrapolated to lie at 6 K but suppressed due to quantum fluctuations. The theory of quantum criticality for such uniaxial ferroelectrics predicts that the temperature dependence of the electric susceptibility χ diverges as 1/ T  3 , in contrast to the 1/ T  2  dependence found in pseudo-cubic materials such as SrTiO 3  or KTaO 3 . In this paper we present evidence of the susceptibility varying as 1/ T  3 , i.e. with a critical exponent γ = 3. In general γ = ( d  +  z  – 2)/ z , where the dynamical exponent for a ferroelectric  z  = 1 and the dimension is increased by 1 from  d   eff   = 3 +  z  to  d   eff   = 4 +  z  due to the effect of long-range dipole interactions in uniaxial as opposed to multiaxial ferroelectrics. The electric susceptibility of the incipient ferroelectric SrFe 12 O 19 , which is slightly further from the quantum phase transition is also found to vary as 1/ T  3 .

Uniaxial ferroelectric quantum criticality in multiferroic hexaferrites BaFe12O19 and SrFe12O19