ELECTRICAL RESISTIVITY MEASUREMENTS UNDER HYDROSTATIC CONDITIONS UP TO 10 GPa

HAL Id: jpa-00224369

https://hal.archives-ouvertes.fr/jpa-00224369

Submitted on 1 Jan 1984

HAL is a multi-disciplinary open access archive for the deposit and dissemination of sci- entific research documents, whether they are pub- lished or not. The documents may come from teaching and research institutions in France or abroad, or from public or private research centers.

L’archive ouverte pluridisciplinaire HAL, est destinée au dépôt et à la diffusion de documents scientifiques de niveau recherche, publiés ou non, émanant des établissements d’enseignement et de recherche français ou étrangers, des laboratoires publics ou privés.

ELECTRICAL RESISTIVITY MEASUREMENTS UNDER HYDROSTATIC CONDITIONS UP TO 10

GPa

G. Andersson, B. Sundqvist, G. Bäckström

To cite this version:

G. Andersson, B. Sundqvist, G. Bäckström. ELECTRICAL RESISTIVITY MEASUREMENTS UN-

DER HYDROSTATIC CONDITIONS UP TO 10 GPa. Journal de Physique Colloques, 1984, 45 (C8),

pp.C8-379-C8-382. �10.1051/jphyscol:1984867�. �jpa-00224369�

JOURNAL DE PHYSIQUE

Colloque C8, supplément au n ° l l , Tome 45, novembre 198** page C8-379

ELECTRICAL R E S I S T I V I T Y MEASUREMENTS UNDER HYDROSTATIC CONDITIONS UP TO 10 GPa

G. A n d e r s s o n , B. S u n d q v i s t and G. Backstrom

Department of Physics, University of limed., S-901 87 limed., Sweden

Résumé - Un système d'enclumes selon Bridgman, mais de grandes dimensions, a ete construit. Des joints d'acier inoxydable permettent de contenir un mélange méthanol-éthanol d'un volume de 500-250 mm

. Pour les mesures électriques on utilise jusqu'à 12 fils passant entre le joint et l'enclume.

On atteint régulièrement 7,5 GPa avec des enclumes d'acier ASP. La transi- tion Bi III-V se présente à une pression plus basse que la moyenne générale- ment acceptée. La résistance de cuivre a été mesurée jusqu'à 6 GPa dans un milieu hydrostatique.

Abstract - A large scale Bridgman anvil system has been designed. Steel gaskets permit compression of a methanol-ethanol medium over a volume of 500-250 mm

. Up to 12 wires have been used to contact specimens. The system has so far served up to 7.5 GPa, with anvils made of ASP tool steel. The transition Bi III-V was found to occur at a lower pressure than the re- commended average. The electrical resistance of copper was measured up to 6 GPa under hydrostatic conditions.

The diamond anvil cell is to-day the preferred high pressure device above 3 GPa. It is excellently suited for optical and X-ray studies, but its small size (about 0.01 mm

) makes it difficult to use for all types of electrical measurements. Attempts have been made /1,2/ to measure resistance by 2- and 4-probe techniques under hydro- static as well as non-hydrostatic pressures, but the experimental difficulties are formidable and high precision results are still rare. A much larger device in the shape of a tungsten carbide (WC) Bridgman anvil, having 5 mm diameter and a steel gasket, was developed by Fasol and Schilling / 3 / . Their cell has a volume of 3 mm

and permits 4 probe resistance measurements under pressure up to 9 GPa.

An experimental problem which has not been discussed is the size of the junctions providing the potential taps. If the diameter of the contact area is 0.01 mm, say, the distance between the potential leads should be about 1 mm to enable resistivity measurements with an accuracy of 1 %. Even if measurements are only relative to the

resistance at room pressure, the difference in compressibility between wire and specimen might modify the contact area as a function of pressure. Access to larger volumes is thus an important requirement for resistivity studies. We have designed a high-pressure device quite similar to that of Fasol and Schilling /3/. However, since a 5000 ton press was available in our laboratory, we could aim for a much larger size (figure 1). The diameter of the flat area is at present 40 mm but may be increased. The anvils are of WC or high-pressure sintered tool steel (ASP 60 from Kloster Speedsteel, Sweden), the latter material being preferred, since it costs 'less, is easy to machine, can be hardened to 69 on the Rockwell C scale and is extremely tough.

The gasket is machined from austenitic stainless steel (SIS 2352) and profiled to yield a large low-pressure stroke without shrinking of the central hole, which ini- tially has a diameter of 12 mm. The cavity is filled with a 4:1 mixture of methanol

Article published online by EDP Sciences and available at http://dx.doi.org/10.1051/jphyscol:1984867

J O U R N A L DE PHYSIQUE

F i g . 1 - C r o s s - s e c t i o n o f t h e new h i g h p r e s s u r e device, showing a n v i l s and g a s k e t . and e t h a n o l , which i s known t o remain h y d r o s t a t i c up t o 10 GPa / 4 / . We n o r m a l l y l e a d 12 i n s u l a t e d w i r e s o u t o f t h e c e l l t h r o u g h s h a l l o w grooves, spark-eroded i n t h e b o t - tom o f t h e g a s k e t and f i l l e d w i t h Al,O,-loaded epoxy r e s i n . I n t h e most complex ex- p e r i m e n t so f a r we measured t h e r e s i s t a n c e o f t h r e e specimens u s i n g s e p a r a t e 4 - w i r e c i r c u i t s , w h i l e m o n i t o r i n g t h e t e m p e r a t u r e w i t h an i n t e r n a l thermocouple. Manganin w i r e i s used as a p r e s s u r e gauge, c a l i b r a t i o n p o i n t s a t 2.55, 2.7 and 5.53 GPa /5/

b e i n g p r o v i d e d by a c o a x i a l w i r e /6/ o f B i and Ba ( o r T I ) . We r e g u l a r l y r e a c h 7.5 GPa, which r e q u i r e s a l o a d o f 900 t o n s . The c e l l volume a v a i l a b l e a t t h i s p r e s s u r e i s a b o u t 250 mm3.

PRESSURE <GPO>

F i g . 2 - R e s i s t a n c e o f one c o a x i a l Bi-Ba c a l i b r a t i o n w i r e vs. p r e s s u r e

7 - z

, , . ^{, , ,}

.--. . - .- . -. .. ..._

,. -- ^{- - -- -} .-- ^- .. -. . ^{-- -} _-

--. -

\

' -7 ^..*

\ ^\ C

', _\ ^\ _{&\ .}

s!. ^i\

I 'i

1 . , . , 1 . . , . 1 . . . .

6. 0 6. 5 7.0 7 . 5 8. 0

PRESSURE (GPO)

F i g . 3 - R e s i s t a n c e vs. p r e s s u r e f o r 3 d i f f e r e n t Bi-Ba w i r e s a t t h e upper B i t r a n - s i t i o n . R e s i s t a n c e s c a l e s have been s h i f t e d v e r t i c a l l y f o r c l a r i t y . We measure a l l r e s i s t a n c e s u s i n g a c e n t r a l f a c i l i t y , c o n s i s t i n g o f a scanner and a 6 a - d i g i t v o l t m e t e r ( H e w l e t t Packard 3495A and 3456A), b o t h c o n t r o l l e d b y a PDP 11/34 computer .

F i g u r e 2 shows t h e r e s i s t a n c e o f one Bi-Ba w i r e p l o t t e d v e r s u s pressure, as c a l c u - l a t e d f r o m t h e Manganin r e s i s t a n c e . The sharpness o f a l l t r a n s i t i o n s i n d i c a t e t h a t t h e medium i s h y d r o s t a t i c . To t e s t t h e p r e s s u r e c a p a b i l i t i e s o f t h e a n v i l system we made t h r e e p r e s s u r e r u n s t o j u s t above t h e upper B i t r a n s i t i o n , which i s g e n e r a l l y c o n s i d e r e d t o o c c u r a t 7.7 GPa / 5 / . F i g u r e 3 shows t h e e x p e r i m e n t a l r e s u l t s f o r t h e r e s i s t a n c e s a g a i n s t P o f t h e i n d i v i d u a l Bi-Ba w i r e s a t t h e t r a n s i t i o n . A l t h o u g h t h e t r a n s i t i o n has p r e v i o u s l y been r e p o r t e d t o be a l m o s t i n s t a n t a n e o u s /7/, we f o u n d i t t o proceed g r a d u a l l y o v e r an a p p r e c i a b l e range i n pressure. I n a l l cases t h e ob- s e r v e d t r a n s i t i o n p r e s s u r e was a l s o below t h e accepted v a l u e o f 7.7 GPa / 5 / . These l o w values f o r t h e t r a n s i t i o n p r e s s u r e may be e x p l a i n e d e i t h e r by an i n t r i n s i c non- 1 i n e a r i t y i n t h e Manganin gauge o r by extreme v i s c o s i t y (even f r e e z i n g ) o f t h e 1 i q u i d medium. The l a t t e r a l t e r n a t i v e i s made p l a u s i b l e by t h e o b s e r v a t i o n /8/ t h a t t h e h y d r o s t a t i c l i m i t i s l o w e r f o r r e s i s t a n c e t h a n f o r f l u o r e s c e n c e gauges. On t h e o t h e r hand i t can n o t be excluded t h a t t h e t r a n s i t i o n mechanism i n t h i s p a r t i c u l a r case c o u l d produce c r y s t a l l i z a t i o n a t d i f f e r e n t p r e s s u r e s above t h e e q u i l i b r i u m p o i n t . The accepted v a l u e , 7.7 GPa, f o r t h e t r a n s i t i o n p r e s s u r e c o u l d a l s o be t o o low, however, s i n c e v a l u e s o f 7.2 and 7.35 GPa have a l s o been r e p o r t e d / 5 / . As a f i r s t r e s e a r c h a p p l i c a t i o n we made two s e p a r a t e r e s i s t a n c e measurements on copper w i r e o f commercial grade. Our r e s u l t s may be summarized by g i v i n g t h e r e - s i s t a n c e , R, as t h e r e s i s t a n c e a t ambient pressure, R,, m u l t i p l i e d by a - p o l y n o m i a l i n P (GPa).

F i g u r e 4 shows B r i d g m a n ' s h y d r o s t a t i c r e s u l t s /9/ and o u r i n d i v i d u a l d a t a p o i n t s

as d i f f e r e n c e s f r o m t h e p o l y n o m i a l e x p r e s s i o n . Our d a t a up t o 3 GPa e v i d e n t l y agree

JOURNAL DE PHYSIQUE

PRESSURE (GPO)

F i g . 4 - I n d i v i d u a l d a t a p o i n t s f r o m two r e s i s t a n c e measurements on copper p l o t t e d as d e v i a t i o n s f r o m Eq. ( 1 ) . Dots - sample 1, t r i a n g l e s - sample 2, f u l l c u r v e - Bridgman /9/.

w e l l w i t h those o f Bridgman, and t h e s m a l l d e v i a t i o n i s o f t h e s i g n expected i f im- p u r i t i e s a r e p r e s e n t .

Most e x p e r i m e n t s so f a r have t e r m i n a t e d by f a i l u r e o f one o f t h e w i r e s . Our i n t e n - t i o n i s t o e x t e n d t h e range o f o p e r a t i o n t o 10 GPa, and we e x p e c t t o r e a c h t h i s l i m i t w i t h t h e p r e s e n t t y p e o f t o o l s t e e l a n v i l . E x t e n t i o n t o l o w e r and h i g h e r temperatures a r e a l s o planned, as w e l l as H a l l e f f e c t measurements.

T h i s work was f i n a n c i a l l y s u p p o r t e d by t h e Swedish N a t u r a l Science Research C o u n c i l .

References

JAYARAMAN A., Rev. Mod. Phys. 55 (1983) 65 REICHLIN R.L., Rev. S c i . I n s t r u m . 54 (1983) 1674

FASOL G., SCHILLING J.S., Rev. Sci,Instrum. 49 (1978) 1722

PIERMARINI G.J., BLOCK S., BARNETT J.D., J. A E l . Phys. 44 (1973) 5377 BEAN V.E., I n : H i g h P r e s s u r e Measurement Techniques, PEGE G.N. (ed.), A p p l i e d Science Pub1 i s h e r s , London (1983) 93

ALM O., ANDERSSON P., BKCKSTROM G., Rev. S c i . I n s t r u m . 45 (1974) 594

MI1 H., FUJISHIRO I . , NOMURA T., I n : Les P r o p r i e t e s PhySiques des S o l i d e s sous P r e s s i o n , GEORGES R. (ed.), E d i t i o n s du CNRS, P a r i s (1970) 441

NOMURA M., NISHIZAKA T., HIRATA Y., NAKAGIRI N.. FUJIWARA H.. J ~ D . _.

J. ADD].

.

Phys. 21 (1982) 936

B R I D G m P.W., Proc. Am. Acad. A r t s S c i . 72 (1938) 157