Huge magnetocrystalline anisotropy in cubic rare earth-Fe2 compounds

ErFe, __

2

ksst

4

square mdysis

_;

295OK .._-

T: 295-H

1

I

6

8

-I

0I’ thcsc d3la. wc find Kl

X IOh mJ K2 = ‘-9 X 10” (ergicm3).

Ihe niagnetir.ation

= .-..:.3

This is in good

agreement

with

und 77°K.

becausc of ;L very large magnetic

20

0

10

rcsults. At 35°K anisl~tro-

incthl

40

[ 71. wc coniputc

80

the ratio of the anisotropy

cons1mts of the RFe, mnpounds ;lt T = 0°K. In table I WC show the room temperalure values for Kl

of the RFe,

cIm1pounds

(Ii = Tb. Dy. Iio.

py the torque is almat linear with applied field mglc. 0,,. for all angles. In fxt. in our highest fields. the

TM) ~slculrlted frm this ratill and the thecmticsl temperature dcpcndence of C’allen 2nd Callen. VLIIUCS

rnasin~unl

of the normalized mgnetimtion. c3lsulation were taken directly

deviation

easy direction

of the niugnetimtion

is only

12.5” at 225°K:

from the 31 77“K.

lhc

deviation

is less than 2”. We GilL’ul3tC 3 v3lue of/i,

at 235°K

equal 10

niagnetimtivn

I .I X IO7 crg,/cm3.

Cillrn

dependence

to their theory

lh3t frmi

of the anisotropy

pounds.

niagnrtization

was calculalcd

da13 of Burm

1’11. The signs of Kl

Ilie

from the mgiietiL3tion agree in all cases

from %l;fsshauer data [ 101. Slrtc

rhul ~hc rl.rom temperature

anisotropies

elf ThFe,

and

camstant.

mugnetization

For 0°K.

WC find Kl

This value for lhc cubic L~lvcs

is of the smie order of niagnirudc

3s lhe

- .- .._. RI+:

_.-Kt

X 11.1’ tcrgimi3)

_ -- ...- .._.. . ix-1 /MI (koc 1

cncrgy of the k~.~a~~mzl rarr’ earth clc-

nienls thernselvcs. which arc the largesl known. The evaluation of the 0°K miso1ropy of one of the RFe, compounds. ErFe2. makes it possible to estimate

data for TbFe, I IoFe,.

a 0°K value. We fin our da13

and Will [hl.

= -.3 X I O8 erg/‘cm3.

1x1 and ErFe? [hj. For lrntl Trl~Fe~. the rm earth sublalticc

frxtion DyFe,.

with those obtained

using the L;.r sublattice

data 01’ Harpouth

anisotropy

10 lKl I.

A’ I > I O8 crg/cn$.

iI is possible to estimate

co~~ipou~ids

only 3 lower limit

arid Callc~i 151 have shown

tenipcraturc

the

rcniains so close to the easy direction

that it is possible to obtain For 77°K.

At 77°K.

necessary for the from the nculrun dif-

the anisotropy Employing

constants

of the rctmining

the Stevens equivalent

corn-

operator

Tb I:c2

3.6

I)yI:rl

2.5

78

IlOt+~

I.2

41

kIri:rq I

0.33

2s

‘I-111Pc 1

Ct.15

41

--_.

_-._ . .

_.. .-.

I In

161

[I

1 E.N.K. li.J.

I’;lyhv.

Slrn;1l.

Aclv. in Ph)s.

31

I I U7 I I 51 I lUTZI

A.I.1’. Cm11. I’nIb.. %I. 5

I : 1114~.