magneto-
(mægˈniːtəʊ)
formally repr. the combining form of Gr. µάγνητ-, µάγνης magnet, first occurring in quasi-Greek derivatives like magnetometer, and now used without restriction to form combinations (chiefly written with hyphen) denoting processes carried on by magnetic means, or the application of magnetism to particular departments of art or industry, as in magneto-electro-telluric, magneto-induced, magneto-inductive, magneto-optic, magneto-optical adjs.; magneto-generator, magneto-induction, magneto-rotation. Also in the following: magneto-bell, magneto-call-bell, an electric bell in which the armature of the electro-magnet is polarized; magˌnetoˈcaloric a. [ad. F. magnétocalorique (Weiss & Piccard 1918, in Compt. Rend. CLXVI. 352)], applied to the reversible change of temperature that accompanies a change in the magnetization of a paramagnetic or ferromagnetic material; magˌnetoˈcardiogram Med., a record of the variations in the magnetic field of a patient's body that occur as a result of the beating of the heart; so magˌnetoˈcardiograph, an instrument used to make such records; magˌnetocardioˈgraphic a., -cardiˈography; magˌnetoˈchemistry, the branch of science concerned with the relation between magnetism and chemical phenomena, molecular and atomic structure, etc.; so magˌnetoˈchemical a.; magneto-dynamo (see quot.); magˌneto-exˈploder, a magneto-electric apparatus for firing an explosive charge; magneto-instrument (Cent. Dict. 1890), -machine, a magneto-electric machine; magˌneto-iˈonic a., of or pertaining to the joint effect of a magnetic field and ionized gas (e.g. in the ionosphere) on the propagation of radio waves; magˌneto-meˈchanical a., pertaining to the interrelation of magnetic and mechanical properties, esp. the magnetic moment and angular momentum of an atom or particle; spec. applied to the ratio of these quantities (or its reciprocal); magneto-optics, the branch of physics which deals with the optical effects of magnetic fields; magneto-phonograph, a sound-recording and producing instrument worked by means of magnetic electricity; magneto-pointer (in mod. Dicts.), the index of a magneto-electric dial telegraph; magneto-printer (in mod. Dicts.), a recording telegraph worked by magneto-electricity; magˌnetoreˈsistance, dependence of the electrical resistance of a body on an external magnetic field; magˌnetoˈsonic a., pertaining to or designating a type of magnetohydrodynamic wave that has two speeds of propagation (both functions of the magnetic field strength and the speed of sound in the fluid), can travel in any direction relative to that of the field, and is characterized by a displacement of the fluid in any direction in the plane defined by the directions of propagation and of the field except the direction normal to the former; magˌnetoˈstatic a., -ˈstatically adv.; magˌnetoˈstatics [after electrostatics], the branch of physics dealing with unchanging magnetic fields; so magˈnetotail [tail n.1], the broad, elongated part of the magnetosphere that extends from the vicinity of the earth in a direction away from the sun; magneto-telegraph (in mod. Dicts.), a telegraph worked by magneto-electricity; magneto-telephone, a magneto-electric sound transmitter; magˌnetoteˈlluric a., pertaining to or designating a technique for investigating the electrical conductivity of the earth by measuring simultaneously fluctuations in its magnetic and electric fields at the surface; hence magˌnetoteˈllurics [-ic 2], the branch of geophysics concerned with this; magneto-therapy, the treatment of disease by the external application of metal plates inducing magnetic electricity (Syd. Soc. Lex. 1889); magneto-transmitter (in mod. Dicts.), a magneto-electric machine for the transmission of (a) electric force, (b) sound.
| 1889 Preece & Maier Telephone Index, *Magneto Bell. |
| 1884 Knight Dict. Mech. Suppl., *Magneto Call-bell, the sounder of a telephone circuit. |
| 1921 Sci. Abstr. A. XXIV. 724 (heading) *Magneto⁓caloric effect. 1937 J. W. T. Spinks tr. Herzberg's Atomic Spectra & Atomic Struct. vi. 211 The magnetocaloric effect [in paramagnetic substances] is so small at room temperature that it cannot be observed. 1965 A. H. Morrish Physical Princ. Magn. iii. 83 Since for a normal paramagnetic salt (∂M/∂T)H is negative, an increase in the field produces a heating and conversely decreasing H gives rise to a temperature drop. This is often called the magnetocaloric effect. The important application of this effect is in the production of temperatures below 1°K. |
| 1963 Baule & McFee in Amer. Heart Jrnl. LXVI. 95/1 The electromotive forces of the heart set up currents in the torso which in turn produce magnetic fields. These fields are exceedingly small... Nevertheless, they may be detected, as is shown by the *magnetocardiogram. 1971 New Scientist 10 June 631/2 As well as being more convenient, a magnetocardiogram (MKG) is faster to take than an electrocardiogram. |
| 1963 Amer. Heart Jrnl. LXVI. 96/2 The *magnetocardiograph offers the potentiality of detecting otherwise ‘silent’ components of the electromotive forces of the heart. 1967 N.Y. Times 6 May 33 Dr. Cohen said..it is..too early to assess the long-range potential of the magnetocardiograph. 1970 Amer. Heart Jrnl. LXXIX. 231/2 Since the electromotive surface representing the activation boundaries lies in the heart, electrocardiographic or magnetocardiographic lead fields need only be known within this region. |
| 1967 Bull. Exper. Biol. & Med. LXIV. 1024 *Magnetocardiography is also valuable as an addition to electrocardiography. |
| 1911 Jrnl. Chem. Soc. C. ii. 367 (heading) *Magneto-chemical researches on the atomic structure of the halogens. 1943 P. W. Selwood Magnetochem. iii. 58 The dimerization of free radicals and of other paramagnetic molecules is one of the most fruitful fields for magnetochemical research. 1972 Indian Jrnl. Chem. X. 726/2 A magnetochemical study of these derivatives has also been carried out to get some information about the nature of bonding of the metal ions with the polyphosphate chain. |
| 1914 Chem. Abstr. VIII. 2648 (heading) *Magneto-chemistry. 1937 Nature 20 Mar. 489/1 By magnetochemistry is meant the examination of the problems of chemical structure in the light of magnetic measurements and modern magnetic theory. 1969 Jrnl. Leeds Univ. Union Chem. Soc. XI. 42 The earliest significant work on magnetochemistry was probably by Faraday who devised a method for measuring susceptibility which is still used today. 1973 Nature 31 Aug. p. xi (Advt.), Magnetochemistry, especially the study of metal–metal interactions in paramagnetic clusters. |
| 1884 S. P. Thompson Dynamo-Electr. Machinery 199 In *magneto-dynamos, in which the field is due to permanent magnets of steel. |
| 1846 J. Joyce Sci. Dial. vi. 423 The machine in this case has been termed the *magneto-electro-telluric machine. |
| 1869 Chambers's Jrnl. Apr. 271/2 A *magneto-exploder..was shewn, which will fire a fuse, and consequently a cannon. 1908 Installation News II. 149/2 Water-tight bells and magneto exploders for blasting purposes. |
| 1893 Preece & Stubbs Man. Telephony 125 The Ericsson-Bell Company's *magneto generators. |
| 1871 Eng. Mechanic 3 Feb. 480/1 He is referring to a galvanic, and not a *magneto-induced current. |
| 1892 S. P. Thompson Magneto-Electr. Machinery 8 Within a few months machines on the principle of *magneto-induction had been devised by Dal Legro and by Pixii. |
| 1879 G. B. Prescott Sp. Telephone 259 The *magneto-inductive waves were superposed. |
| 1925 Appleton & Barnett in Electrician 3 Apr. 398/1 The same theory (for which we propose the name *magneto-ionic theory) has also been independently put forward by Messrs. Nicholls and Schelling (‘Nature’, March 7th, 1925). 1932 E. V. Appleton in Jrnl. Inst. Electr. Engin. LXXI. 645/2 It is highly probable that interference between the various magneto-ionic components of singly- and multiply-reflected downcoming waves is partly responsible for resultant intensity fading. 1973 Physics Bull. May 291/3 A first start is made to the problem of the transfer of radio emission in a pulsar magnetosphere by applying the method of magnetoionic theory. |
| c 1865 G. Gore in Circ. Sci. I. 229/1 The *magneto-machine being in some cases employed. 1891 S. P. Thompson tr. Guillemin's Magn. & Electr. 415 Gramme's magneto-machine. |
| 1925 Sci. Abstr. A. XXVIII. 611 *Magneto-mechanical anomaly of the atom. 1930 Magneto-mechanical [see gyromagnetic a. 1]. 1950 W. Finkelnburg Atomic Physics iii. 153 The magnetic moment of paramagnetic atoms is due to the electron rotating in its orbit or to the spin of the electron. The so-called magnetomechanical parallelism enables us to distinguish between these two contributions to the atomic magnetism. 1953 [see gyromagnetic a. 1]. 1958 Condon & Odishaw Handbk. Physics iv. viii. 136/1 Because of the magnetomechanical interactions.., internal stresses due to cold-working, impurities, precipitates, etc., contribute a spatially varying component of the short-range energy. |
| 1881 S. P. Thompson Elem. Electr. & Magnet. §387. 350 *Magneto-optic Rotation of the Plane of Polarisation of a Ray of Light. |
| 1913 P. Zeeman Res. Magneto-Optics p. xi, To the memory of this sage [sc. Faraday]—..the pioneer in *magneto-optics as in so many things, I have ventured to dedicate this volume. 1960 Physical Rev. Lett. IV. 357 (heading) Photon momentum effects in the magneto-optics of excitons. |
| 1848 Faraday in Phil. Trans. CXXXIX. 35 Plücker's *magneto-optical results. 1850 Tyndall in Rep. Brit. Assoc., Sections (1851) 23 On the Magneto-Optical Properties of Crystals. |
| 1902 J. J. Thomson in Encycl. Brit. XXX. 464 *Magneto-Optics. |
| 1902 Harper's Mag. Feb. 496 It has been variously designated as the ‘telegraphone’, the ‘microphonograph’ and the ‘*magneto-phonograph’ in Europe. |
| 1930 L. W. McKeehan in Physical Rev. XXXVI. 949 The *magneto-resistance effect in non⁓ferromagnetics is only measurable with accuracy in very intense magnetic fields. 1961 Engineering 22 Dec. 823 One of the first practical devices to use the phenomenon of magnetoresistance is a voltage regulator. 1966 New Scientist 3 Feb. 286/2 The magnetoresistance effect in semiconductors, which has recently been shown to exist at frequencies well up into the microwave region. |
| 1889 Syd. Soc. Lex., *Magneto-rotation. |
| 1962 W. B. Thompson Introd. Plasma Physics v. 84 There is remarkably little evidence for the propagation of *magnetosonic waves through a plasma. Ibid. 91 In the magnetohydrodynamic case, there are three possible parametrizing velocities Cs, CA and the magnetosonic speed CT= √(CA2+Cs2). 1971 Nature 13 Aug. 443/3 The Crab pulsar..seems to be associated with a series of wisps of gas... Wisps 2, 3 and 4 have been generated by the magnetosonic waves which this motion of Wisp 1 produces. |
| 1893 Notices Proc. R. Inst. Gt. Brit. XIII. 348 *Magneto⁓static screening by soft iron would follow the same law as electrostatic screening, if the magnetic susceptibility of the iron were infinitely great. 1950 Physical Rev. LXXV. 156 The domain patterns..represent configurations of low magnetostatic energy. 1969 M. A. Uman Lightning 101 The magnetostatic field present during a lightning discharge is directly proportional to the discharge current. |
| 1960 Physical Rev. Lett. V. 47/1 The figure of 10-8 erg/cm3 represents..a solar wind flux sufficient to compress the geomagnetic field *magnetostatically to ∼9Re if we utilize the usual model. |
| 1897 A. G. Webster Theory Electr. & Magn. ix. 353 (heading) Parallel treatment of electrostatics and *magnetostatics. 1952 E. G. Ramberg tr. Sommerfeld's Electrodynamics i. 40 In most treatments the analogy between electrostatics and magnetostatics is emphasized. 1968 J. C. Anderson Magnetism i. 10 In magnetostatics it is convenient to define a magnetic pole strength, q, analogous to electric charge. |
| 1971 Daily Tel. 4 Aug. 4/3 This region's outlines become distorted by a varying stream of electrified atomic particles from the Sun called solar wind. It sweeps part of the magneto⁓sphere..into a tear-drop shape which scientists would now refer to as the Earth's *magnetotail. 1973 Nature 9 Mar. 79/2 The multiple satellite mission will help unravel the spatial and temporal variations of the radiation belt, the magnetopause, the bow shock and magnetotail. |
| 1883 S. P. Thompson P. Reis 9 In 1877, when the *Magneto-Telephones of Graham Bell began to make their way into Europe. |
| 1953 L. Cagniard in Geophysics XVIII. 605 (heading) Basic theory of the *magneto-telluric method of geophysical prospecting. 1967 L. R. Alldredge in Matsushita & Campbell Physics of Geomagn. Phenomena I. i. ii. 55 Smith et al...describe instrumentation for magneto⁓telluric experiments for which simultaneous measurements of geomagnetic micropulsations and telluric currents are made. 1971 Nature 3 Sept. 13/1 To learn something about the behaviour of the upper mantle..Tammemagi and Lilley..have made four magnetotelluric soundings at 150 km intervals roughly along the latitude of Canberra. |
| 1960 Jrnl. Geophysical Res. LXV. 4202/1 Useful field results have not been numerous in the literature, and field *magnetotellurics is still in the developmental stage. 1967 A. T. Price in Matsushita & Campbell Physics of Geomagn. Phenomena I. ii. iii. 295 There is, at present, much activity in the theory and practice of magnetotellurics, which should greatly help the task of unravelling and interpreting many geomagnetic phenomena. |