The effect of hydrogen on the magnetostriction of rare-earth compounds TbxDy₁₋xFe₂
The crystal structure and the magnetic and magnetoelastic properties of TbxDy₁₋xFe₂Hy (x = 0.27; 0.41; y ≤ 3) are investigated. The hydrides are obtained by the interaction of TbxDy₁₋xFe₂ samples with hydrogen gas at room temperature. It is established that the hydrides have the same cubic type of s...
Збережено в:
| Дата: | 2001 |
|---|---|
| Автори: | , , , , , |
| Формат: | Стаття |
| Мова: | English |
| Опубліковано: |
Фізико-технічний інститут низьких температур ім. Б.І. Вєркіна НАН України
2001
|
| Назва видання: | Физика низких температур |
| Теми: | |
| Онлайн доступ: | http://dspace.nbuv.gov.ua/handle/123456789/130018 |
| Теги: |
Додати тег
Немає тегів, Будьте першим, хто поставить тег для цього запису!
|
| Назва журналу: | Digital Library of Periodicals of National Academy of Sciences of Ukraine |
| Цитувати: | The effect of hydrogen on the magnetostriction of rare-earth compounds TbxDy₁₋xFe₂ / S.A. Nikitin, I.S. Tereshina, A.P. Touliakov, E.A. Tereshina, V.N. Verbetsky A. A. Salamova // Физика низких температур. — 2001. — Т. 27, № 4. — С. 403-405. — Бібліогр.: 8 назв. — англ. |
Репозитарії
Digital Library of Periodicals of National Academy of Sciences of Ukraine| id |
irk-123456789-130018 |
|---|---|
| record_format |
dspace |
| spelling |
irk-123456789-1300182018-02-05T03:02:46Z The effect of hydrogen on the magnetostriction of rare-earth compounds TbxDy₁₋xFe₂ Nikitin, S.A. Tereshina, I.S. Touliakov, A.P. Tereshina, E.A. Verbetsky, V.N. Salamova, A.A. Низкотемпеpатуpная магнитостpикция магнетиков и свеpхпpоводников The crystal structure and the magnetic and magnetoelastic properties of TbxDy₁₋xFe₂Hy (x = 0.27; 0.41; y ≤ 3) are investigated. The hydrides are obtained by the interaction of TbxDy₁₋xFe₂ samples with hydrogen gas at room temperature. It is established that the hydrides have the same cubic type of structure as the parent compounds but the lattice parameter in the hydrides is larger than in the hydrogen-free samples. Both the Curie temperature and the magnetic moment decrease drastically as the hydrogen concentration increases. Measurements of the longitudinal λ|| and transverse magnetostriction λ^ are carried out in magnetic fields up to 12 kOe in the temperature range 78√300 K using strain gauges.The thermal expansion coefficients as a function of temperature are obtained for hydrides with high hydrogen concentration. The magnetostriction of hydrides is strongly different from that of hydride-free samples. The small and negative value of the magnetostriction at low temperatures proves that hydrogen atoms make a strong contribution to the crystal field acting on the rare-earth ions. 2001 Article The effect of hydrogen on the magnetostriction of rare-earth compounds TbxDy₁₋xFe₂ / S.A. Nikitin, I.S. Tereshina, A.P. Touliakov, E.A. Tereshina, V.N. Verbetsky A. A. Salamova // Физика низких температур. — 2001. — Т. 27, № 4. — С. 403-405. — Бібліогр.: 8 назв. — англ. 0132-6414 PACS: 74.25.Ha;, 75.30.Gw http://dspace.nbuv.gov.ua/handle/123456789/130018 en Физика низких температур Фізико-технічний інститут низьких температур ім. Б.І. Вєркіна НАН України |
| institution |
Digital Library of Periodicals of National Academy of Sciences of Ukraine |
| collection |
DSpace DC |
| language |
English |
| topic |
Низкотемпеpатуpная магнитостpикция магнетиков и свеpхпpоводников Низкотемпеpатуpная магнитостpикция магнетиков и свеpхпpоводников |
| spellingShingle |
Низкотемпеpатуpная магнитостpикция магнетиков и свеpхпpоводников Низкотемпеpатуpная магнитостpикция магнетиков и свеpхпpоводников Nikitin, S.A. Tereshina, I.S. Touliakov, A.P. Tereshina, E.A. Verbetsky, V.N. Salamova, A.A. The effect of hydrogen on the magnetostriction of rare-earth compounds TbxDy₁₋xFe₂ Физика низких температур |
| description |
The crystal structure and the magnetic and magnetoelastic properties of TbxDy₁₋xFe₂Hy (x = 0.27; 0.41; y ≤ 3) are investigated. The hydrides are obtained by the interaction of TbxDy₁₋xFe₂ samples with hydrogen gas at room temperature. It is established that the hydrides have the same cubic type of structure as the parent compounds but the lattice parameter in the hydrides is larger than in the hydrogen-free samples. Both the Curie temperature and the magnetic moment decrease drastically as the hydrogen concentration increases. Measurements of the longitudinal λ|| and transverse magnetostriction λ^ are carried out in magnetic fields up to 12 kOe in the temperature range 78√300 K using strain gauges.The thermal expansion coefficients as a function of temperature are obtained for hydrides with high hydrogen concentration. The magnetostriction of hydrides is strongly different from that of hydride-free samples. The small and negative value of the magnetostriction at low temperatures proves that hydrogen atoms make a strong contribution to the crystal field acting on the rare-earth ions. |
| format |
Article |
| author |
Nikitin, S.A. Tereshina, I.S. Touliakov, A.P. Tereshina, E.A. Verbetsky, V.N. Salamova, A.A. |
| author_facet |
Nikitin, S.A. Tereshina, I.S. Touliakov, A.P. Tereshina, E.A. Verbetsky, V.N. Salamova, A.A. |
| author_sort |
Nikitin, S.A. |
| title |
The effect of hydrogen on the magnetostriction of rare-earth compounds TbxDy₁₋xFe₂ |
| title_short |
The effect of hydrogen on the magnetostriction of rare-earth compounds TbxDy₁₋xFe₂ |
| title_full |
The effect of hydrogen on the magnetostriction of rare-earth compounds TbxDy₁₋xFe₂ |
| title_fullStr |
The effect of hydrogen on the magnetostriction of rare-earth compounds TbxDy₁₋xFe₂ |
| title_full_unstemmed |
The effect of hydrogen on the magnetostriction of rare-earth compounds TbxDy₁₋xFe₂ |
| title_sort |
effect of hydrogen on the magnetostriction of rare-earth compounds tbxdy₁₋xfe₂ |
| publisher |
Фізико-технічний інститут низьких температур ім. Б.І. Вєркіна НАН України |
| publishDate |
2001 |
| topic_facet |
Низкотемпеpатуpная магнитостpикция магнетиков и свеpхпpоводников |
| url |
http://dspace.nbuv.gov.ua/handle/123456789/130018 |
| citation_txt |
The effect of hydrogen on the magnetostriction of rare-earth compounds TbxDy₁₋xFe₂ / S.A. Nikitin, I.S. Tereshina, A.P. Touliakov, E.A. Tereshina, V.N. Verbetsky A. A. Salamova // Физика низких температур. — 2001. — Т. 27, № 4. — С. 403-405. — Бібліогр.: 8 назв. — англ. |
| series |
Физика низких температур |
| work_keys_str_mv |
AT nikitinsa theeffectofhydrogenonthemagnetostrictionofrareearthcompoundstbxdy1xfe2 AT tereshinais theeffectofhydrogenonthemagnetostrictionofrareearthcompoundstbxdy1xfe2 AT touliakovap theeffectofhydrogenonthemagnetostrictionofrareearthcompoundstbxdy1xfe2 AT tereshinaea theeffectofhydrogenonthemagnetostrictionofrareearthcompoundstbxdy1xfe2 AT verbetskyvn theeffectofhydrogenonthemagnetostrictionofrareearthcompoundstbxdy1xfe2 AT salamovaaa theeffectofhydrogenonthemagnetostrictionofrareearthcompoundstbxdy1xfe2 AT nikitinsa effectofhydrogenonthemagnetostrictionofrareearthcompoundstbxdy1xfe2 AT tereshinais effectofhydrogenonthemagnetostrictionofrareearthcompoundstbxdy1xfe2 AT touliakovap effectofhydrogenonthemagnetostrictionofrareearthcompoundstbxdy1xfe2 AT tereshinaea effectofhydrogenonthemagnetostrictionofrareearthcompoundstbxdy1xfe2 AT verbetskyvn effectofhydrogenonthemagnetostrictionofrareearthcompoundstbxdy1xfe2 AT salamovaaa effectofhydrogenonthemagnetostrictionofrareearthcompoundstbxdy1xfe2 |
| first_indexed |
2025-07-09T12:42:20Z |
| last_indexed |
2025-07-09T12:42:20Z |
| _version_ |
1837173251177971712 |
| fulltext |
Fizika Nizkikh Temperatur, 2001, v. 27, No. 4, p. 403–405Nikitin S. A ., Te resh in a I. S., T ouliakov A. P., and T ere shina E. A .Th e effe ct of hyd rog en on t he ma gne tostr iction of r ar e-ear th com pou nds Tb xDy1 –xFe 2Nikit in S. A. , Ter eshina I. S., Tou liako v A . P., a nd Ter eshina E . A. The ef fect o f hydr oge n on the m ag neto strict io n of ra re-ea rth c omp ound s T bxDy1– xFe2
The effect of hydrogen on the magnetostriction of
rare-earth compounds TbxDy1–xFe2
S. A. Nikitin, I. S. Tereshina, A. P. Touliakov, and E. A. Tereshina
Department of Physics, Moscow State University, Vorobyevy Gory, 119899, Moscow, Russia
E-mail: nikitin@rem.phys.msu.su
V. N. Verbetsky and A. A. Salamova
Department of Chemistry, Moscow State University, Vorobyevy Gory, 119899, Moscow, Russia
Received October 26, 2000
The crystal structure and the magnetic and magnetoelastic properties of TbxDy1−xFe2Hy (x = 0.27;
0.41; y ≤ 3) are investigated. The hydrides are obtained by the interaction of TbxDy
1−xFe2
samples with
hydrogen gas at room temperature. It is established that the hydrides have the same cubic type of
structure as the parent compounds but the lattice parameter in the hydrides is larger than in the
hydrogen-free samples. Both the Curie temperature and the magnetic moment decrease drastically as the
hydrogen concentration increases. Measurements of the longitudinal λ
||
and transverse magnetostriction
λ⊥ are carried out in magnetic fields up to 12 kOe in the temperature range 78–300 K using strain
gauges.The thermal expansion coefficients as a function of temperature are obtained for hydrides with
high hydrogen concentration. The magnetostriction of hydrides is strongly different from that of
hydride-free samples. The small and negative value of the magnetostriction at low temperatures proves
that hydrogen atoms make a strong contribution to the crystal field acting on the rare-earth ions.
PACS: 74.25.Ha; 75.30.Gw
S. A. N ikitin et al.
Introduction
Intermetallic compounds of rare earths (R) and
3d-transition metals having MgCu2-type crystal
structure are attracting much attention in recent
years as giant magnetostrictive materials [1]. These
compounds interact actively with hydrogen gas at
room temperature and form stable hydrides. Upon
hydrogenation these compounds exhibit substantial
changes in their magnetic properties [2]. The mag-
netoelastic properties of TbxDy1−xFe2 compounds
have been investigated insufficiently up to now,
because the samples are degraded in the process of
hydrogen absorption. We have prepared powder-
pressed samples for all of the compounds, including
the host alloys, and have measured the magnetos-
triction of these compounds. This method was suc-
cessfully applied by Clark et al. [3]. The present
paper reports on the magnetic and magnetoelastic
properties of TbxDy1−xFe2Hy (x = 0.27; 0.41) with
different hydrogen concentrations (y ≤ 3).
Experimental methods
Samples of Tb0.27Dy0.73Fe2 and Tb0.41Dy0.59Fe2
were prepared by melting constituent metals of rare
earth and Fe metals with purities of 99.95% and
99.98%, respectively, in an induction furnace, fol-
lowed by annealing for 40 h at 1000°C. X-ray
diffraction analysis carried out with a powder dif-
fractometer using Cr Kα-radiation showed that all
of the compounds studied were almost single-phase
and had crystalline structures of the MgCu2-type.
The amount of extraneous phases in the samples was
no more than 2%.
The hydrides were obtained by the interaction of
the TbxDy1−xFe2 samples with hydrogen gas at
room temperature. The concentration of absorbed
hydrogen in the samples was calculated using the
van der Waals equation and additionally was
measured by the full-burning method.
Thermomagnetic analysis (TMA) was used to
measure the Curie temperature in a field of 1 kOe.
The magnetic measurements were made for aligned
and free powder samples in the temperature range
© S. A. Nikitin, I. S. Tereshina, A. P.Touliakov, E. A. Tereshina, V. N. Verbetsky, and A. A. Salamova, 2001
80–700 K and in magnetic fields up to 12 kOe,
using a pendulum magnetometer.
The magnetostriction of TbxDy1−xFe2Hy was
measured in fields up to 12 kOe in the temperature
range 80–300 K by using a conventional strain-
gauge bridge. Since the hydrides were available
only in the powder form, the measurements were
made with powder-pressed samples. The fine pow-
der of TbxDy1−xFe2Hy compounds was compacted
under pressure near 3 GPa in disks with dimensions
of 0.8 mm×1.5 mm×8 mm. The densities of the
samples produced in this way were nearly 70% of
the powder x-ray densities. We took as the magne-
tostriction value for the investigated compounds the
values measured on the pressed sample multiplied
by the ratio of the powder x-ray density to the
pressed sample density [3]. This method was
checked on solidified precursor samples. Magnetos-
trictive measurements were made as a function of
magnetic field strength and temperature.
Results and discussion
TbxDy1−xFe2 (x = 0.27; 0.41) compounds were
found to be crystallized in the cubic MgCu2-type
structure (Fig. 1). The lattice constant a and unit
cell volume V are listed in Table. It was observed
that hydrogenation leads to a lattice expansion of
the compounds without change of the cubic struc-
ture from the MgCu2 type. The relative cell volume
increases ∆V/V show a consistent ∼ 9% (at x = 1)
and ∼ 20% (at x = 3) volume expansion over the
hydrogen-free unit cell for all the compounds.
Table
Crystallographic and magnetic data for the Tb
x
Dy
1−x
Fe2
com-
pounds and their hydrides.
Compound a, A° V, A° 3 ∆V/V, % T
C
, K
Tb
0.27
Dy
0.73
Fe
2
7.325 393.03 — 686
Tb
0.27
Dy
0.73
Fe
2
H
1
7.537 428.15 8.9 596
Tb
0.41
Dy
0.59
Fe
2
7.324 392.87 — 697
Tb
0.41
Dy
0.59
Fe
2
H
3
7.789 472.547 20.2 275
The Curie temperatures TC of TbxDy1−xFe2 com-
pounds and their hydrides were determined using
TMA, as was mentioned above (Fig. 2). In cases
when TC was close to room temperatures, it was
obtained from a Belov–Arrott plot (for example, see
Fig. 3). The Curie temperatures of TbxDy1−xFe2Hy
are summarized in Table in comparison with their
original counterparts.
Both the Curie temperature and the magnetiza-
tion decrease with increasing hydrogen concentra-
tion. At y = 3 a compensation temperature appears
in the compound. Such behavior has been observed
earlier [7] and is typical for all RFe2 compounds
(where R is a heavy rare earth).
Figure 4,a shows the temperature dependence of
the magnetization σ(T) measured in an external
magnetic field of 12 kOe. It can be seen from Fig. 4
that the σ-curve measured on heating of the sample
is characterized by a single minimum at T ≈ 130 K
(compensation temperature) and a broad maximum
at T ≈ 220 K.
Fig. 1. Cubic Laves phase (C15). The large circles represent
the rare-earth ions and the small circles represent 3d ions.
Fig. 2. The temperature dependence of magnetization σ of the
TbxDy1−xFe2 compounds measured at an external magnetic field
of 1 kOe: Tb0.41Dy0.59Fe2 (❍); Tb0.27Dy0.73Fe2 (▲);
Tb0.27Dy0.73Fe2H1 (∆); Tb0.41Dy0.59Fe2H3 (●).
S. A. Nikitin et al.
404 Fizika Nizkikh Temperatur, 2001, v. 27, No. 4
Figure 4,b shows the temperature dependence of
longitudinal magnetostriction λ || measured at differ-
ent external magnetic fields. The maximum of the
longitudinal magnetostriction λ || for all the curves
is observed near the TC ≈ 270 K, obtained by the
TMA. Near the compensation temperature the λ ||
longitudinal magnetostriction (Fig. 4,b) changes its
sign and becomes negative at low temperatures.
Anomalies at these temperatures can be also seen on
the thermal expansion curve ∆l/l (see Fig. 4,c).
From these results the following comments can
be made: (i) hydrogenation leads to a simple vo-
lume expansion of the cubic lattice up to 20%;
(ii) the Curie temperature, magnetic moment, and
magnetostriction decrease drastically with increas-
ing hydrogen concentration. As follows from Ref. 8,
hydrogen in RFe2 occupies different positions de-
pending on concentration. Our measurements are
evidence that hydrogen incorporation at high con-
centration (y = 3) strongly influences the crystal
field acting on the rare-earth atoms.
Conclusions
Thus a comprehensive study of the structural,
magnetic, and magnetoelastic properties of the
TbxDy1−xFe2 compounds (x = 0.27; 0.41) and their
hydrides has been made. The interstitial atoms oc-
cupy sites adjacent to the rare-earth atoms, creating
a change of crystal field that reflects the local
symmetry and induces a significant change in the
magnetic properties (Curie temperature, saturation
magnetization, and magnetostriction).
Acknowledgments
We are very grateful to K.P. Skokov for prepara-
tion of the samples. This work has been supported
by RFBR Grants No 99-02-17821 and No 99-03-
32824.
1. Supermagnets: Hard magnetic materials, G. J. Long and
F. Grandjean (eds. ), vol. 331 of NATO Advanced Study
Institute, ser. C, Kluwer Acad. (1991).
2. D. G. R. Jones, P. J. McGuiness, J. S. Abell, and I. R.
Harris, J. Less-Comm. Met. 158, 153 (1990).
3. A. E. Clark, J. P. Teter, and O. D. McMasters, J. Appl.
Phys. 63, 3910 (1988).
4. L. Ruiz de Angulo, J. S. Abell, and I. R. Harris, J. Appl.
Phys. 76, 7157 (1994).
5. S. Annapoorni, G. Markandeyulu, and K. V. S. Rama Rao,
J. Appl. Phys. 65, 4955 (1989).
6. A. E. Clark, S. F. Cheng, J. P. Teter, M. Wung-Fogle,
M. Q. Huang, and Y. Zheng, J. Magn. Magn. Mater. 104,
1433 (1992).
7. A. Ye. Yermakov, N. V. Mushnikov, N. K. Zajkov, V. S.
Gaviko, and V. A. Barinov, Philos. Mag. B68, 883 (1993).
8. N. K. Zajkov, N. V. Mushnikov, A. Ye. Yermakov, Fiz.
Met. Metalloved. 79, 50 (1995) (in Russian).
Fig. 4. The temperature dependence of magnetization σ of
crystalline Tb0.41Dy0.59Fe2H3 samples measured at an external
magnetic field of 12 kOe (a). The temperature dependence of
the longitudinal magnetostriction λ || measured at different
values of external magnetic fields H, kOe: 2 (1), 10 (2), 12
(3) (b); Temperature dependence of the thermal expansion
λt = ∆l/l (c).
Fig. 3. The dependence of H/σ versus σ2 for Tb0.41Dy0.53Fe2H2.8
at different T, K: 280 (❏); 290 (∆), and 302 (●).
The effect of hydrogen on the magnetostriction of rare-earth compounds Tb
x
Dy1–x
Fe2
Fizika Nizkikh Temperatur, 2001, v. 27, No. 4 405
|