# Orthoferrite

> Mediated Wiki article. Canonical URL: https://mediated.wiki/source/Orthoferrite
> Markdown URL: https://mediated.wiki/source/Orthoferrite.md
> Source: https://en.wikipedia.org/wiki/Orthoferrite
> Source revision: 1237718129
> License: Creative Commons Attribution-ShareAlike 4.0 International (https://creativecommons.org/licenses/by-sa/4.0/)

An '''orthoferrite''' is any of a class of [chemical compound](/source/chemical_compound)s with the formula RFeO{{sub|3}}, where R is one or more [rare-earth element](/source/rare-earth_element)s.  Orthoferrites have an [orthorhombic](/source/orthorhombic) crystal structure with a space group Pbnm and most are weakly [ferromagnetic](/source/ferromagnetic).<ref>[http://dictionary.oed.com/cgi/entry/00334125/00334125se11?single=1&query_type=word&queryword=orthoferrite&first=1&max_to_show=10&hilite=00334125se11 "orthoferrite", Oxford English Dictionary, Draft Revision March 2008]</ref>
At the [Néel temperature](/source/N%C3%A9el_temperature) <math>T_N</math> the subsystem of iron ions orders into a slightly canted antiferromagnetic structure with antiferromagnetic moment G and a weak ferromagnetic moment F. The rare-earth ion subsystem acquires magnetization m due to an interaction with the iron subsystem.

The orthoferrites are particularly interesting because of the presence of an [antisymmetric exchange interaction](/source/Antisymmetric_exchange) which involves the [vector cross product](/source/vector_cross_product) of neighboring spins as opposed to the usual [scalar product](/source/scalar_product). In the absence of this interaction, the orthoferrites would be antiferromagnetic. Its presence leads to a small [canting](/source/spin_canting) of the sublattices, making the orthoferrites “weak” ferromagnets with <math>4 \pi M_s = 100 G</math>. Another interesting feature of these materials is the fact that some of them exhibit a transition as a function of temperature, in which the direction of the antiferromagnetically ordered spins and consequently also of the net magnetization rotates by 90°.<ref name="afanasiev">{{cite journal |last1=D. Afanasiev |display-authors=etal |title=Ultrafast control of magnetic interactions via light-driven phonons |journal=Nature Materials |date=8 February 2021 |volume=20 |issue=5 |pages=607–611 |doi=10.1038/s41563-021-00922-7 | issn=1476-1122 |pmid=33558717 |pmc=7610706 |arxiv=1912.01938 |bibcode=2021NatMa..20..607A }}</ref>

==Applications==
The combination of high magnetic resonance frequencies with very large magnetooptical effects makes the orthoferrites interesting objects for study of laser-induced dynamics.
Orthoferrites are transparent, and can modify the [polarisation](/source/Polarization_(waves)) of a beam of [light](/source/light) under the control of a [magnetic field](/source/magnetic_field) ([Faraday rotation](/source/Faraday_rotation)).  This makes them potentially useful as optical sensors and actuators for use in [optical communications](/source/optical_communications).
<ref>Didosyan, Hauser, Reider, Nicolics, [https://ieeexplore.ieee.org/stamp/stamp.jsp?arnumber=1426350 ''Sensors and Actuators on Orthoferrites''], IEEE 2004</ref> They were also once used as the magnetic material in [bubble memory](/source/bubble_memory).

==Examples==
* [Lanthanum](/source/Lanthanum) orthoferrite, LaFeO{{sub|3}}<ref>{{cite journal|last1=Ita|first1=B.|last2=Murugavel|first2=P.|last3=Ponnambalam|first3=V.|last4=Raju|first4=A. R.|title=Magnetic properties of lanthanum orthoferrite fine powders prepared by different chemical routes|journal=Journal of Chemical Sciences|date=2003|volume=115|issue=5–6|pages=519–524|doi=10.1007/BF02708243|s2cid=94892093|url=http://www.iisc.ernet.in/academy/chemsci/Pdf-OctDec2003/Pc3338.pdf}}</ref>
* [Dysprosium](/source/Dysprosium) orthoferrite, DyFeO{{sub|3}}<ref>{{cite journal|last1=Maziewski|first1=A.|last2=Szymczak|first2=R.|title=Visual observation of phase domains in dysprosium orthoferrite|journal=Journal of Physics D: Applied Physics|date=1977|volume=10|issue=4|pages=L37–L38|doi=10.1088/0022-3727/10/4/003|bibcode=1977JPhD...10L..37M|s2cid=250803792 }}</ref>

==References==
{{reflist}}

Category:Iron(III) compounds

---
Adapted from the Wikipedia article [Orthoferrite](https://en.wikipedia.org/wiki/Orthoferrite) by Wikipedia contributors ([contributor history](https://en.wikipedia.org/wiki/Orthoferrite?action=history)). Available under [Creative Commons Attribution-ShareAlike 4.0 International](https://creativecommons.org/licenses/by-sa/4.0/). Changes may have been made.