Site-specific order and magnetism in tetragonal Mn3Ga thin films
File Type:
PDFItem Type:
Journal ArticleDate:
2013Access:
OpenAccessCitation:
Rode, K., Baadji, N., Betto, D., (...), Porcher, F., André, G., Site-specific order and magnetism in tetragonal Mn3Ga thin films, Physical Review B - Condensed Matter and Materials Physics, 87, 18, 2013, Article number 184429Download Item:
PhysRevB.87.184429.pdf (Published (publisher's copy)) 1.541Mb
Abstract:
Mn
3
Ga bulk material and thin films deposited on several different substrates have been investigated using
x-ray and neutron diffraction, x-ray absorption spectroscopy, x-ray magnetic circular dichroism, and electronic
structure calculations using density-functional theory with the aim of determining the atomic site occupancy,
magnetic moments, and magnetic structure of this tetragonal D0
22
-structure compound. The Mn
3
Ga has close
to ideal site occupancy, with Ga on 2
a
sites and Mn on 2
b
and 4
d
sites. The magnetic structure is basically
ferrimagnetic, with the larger Mn moment of about 3
?
B
on the 2
b
site, which is coordinated by 8 Mn 4
d
and
4 Ga, and the smaller one on the 4
d
site, which is coordinated by 4 Mn 2
b
, 4 Ga, and 4 Mn 4
d
.TheMn
d
-band
occupancy is close to 5 on both sites, and the orbital moments are small,
<
0
.
2
?
B
. The material nevertheless
exhibits substantial uniaxial anisotropy,
K
u
=
1
.
0MJm
?
3
, which originates from the 4
d
site. The 2
b
site has hard
axis anisotropy, which together with an oscillatory exchange coupling from the first and second nearest neighbors,
leads to a soft component of the magnetization in the
c
plane, coexisting with
c
-axis hysteresis loops exhibiting
coercivity of up to 1.2 T, and magnetization in the range 110?220 kA m
?
1
at room temperature, depending on
preparation conditions. Tetragonal Mn
2
Ga films behave similarly. Manganese is lost from both sites, but the films
have substantially larger magnetization (480 kA m
?
1
) and anisotropy constant (2.35 MJ m
?
3
)thanMn
3
Ga.
Sponsor
Grant Number
Science Foundation Ireland (SFI)
Internet (08/ERA/I1759)
European Union Framework Programme 7 (FP7)
project IFOX (NMP3-LA-2010-246102).
Science Foundation Ireland (SFI)
10/IN1.13006
Author's Homepage:
http://people.tcd.ie/jcoeyhttp://people.tcd.ie/rodek
http://people.tcd.ie/stamenp
http://people.tcd.ie/sanvitos
http://people.tcd.ie/venkatem
Description:
PUBLISHEDType of material:
Journal ArticleCollections:
Series/Report no:
Physical Review B - Condensed Matter and Materials Physics87
18
Availability:
Full text availableKeywords:
PhysicsSubject (TCD):
Nanoscience & MaterialsDOI:
http://dx.doi.org/10.1103/PhysRevB.87.184429Licences: