WHERE TO NOW?, page-35

A bit more on samarium et al.
http://www.australianminesatlas.gov.au/aimr/commodity/rare_earths.html

Table 1 - Distribution of types of REEs in selected deposits (Arafura Resources Ltd)

Rare Earth Oxide	Application	Nolans Bore %	Mount Weld %	Mountain Pass USA %	Baiyanobo China %
Lanthanum	Petroleum cracking catalysts, batteries (NiMH)	19.74	25.6	33.2	27.1
Cerium	Autocatalyst, glass, polishing	47.53	45.74	49.1	49.86
Praseodymium	Magnets, glass	5.82	5.42	4.34	5.15
Neodymium	Magnets (NdFeB)	21.2	18.62	12.0	15.4
Samarium	Magnets, (SmCo)	2.37	2.44	0.8	1.15
Europium	Phosphors, nuclear control applications	0.4	0.55	0.12	0.19
Gadolinium	Intravenous contrast agents, phosphors	1.0	0.97	0.17	0.4
Terbium	Phosphors	0.08	0.09
Dysprosium	Magnets (NdFeB), lasers	0.33	0.16		0.3
Other Rare Earths (Ho, Er, Tm, Yb, Lu)		0.21	0.04	0.16	0.03
Other elements
Yttrium	Phosphors, metal alloys	1.32	0.37	0.1	0.2

Samarium (SmCo5) produces the most temperature stable magnets, but they are brittle and low on tensile strength. (Fig 1 previous post)

Mechanical properties of Alnico are superior than most of the permanent magnets, except the bonded REE magnets. The tensile strength for Alnico, SmCo5, and NdFeB are 350, 41, and 82 MPa, respectively. And the fracture toughness (KIC) of these three magnetic materials are 13.3, 5.5, and 1.9 MPa m0.5, respectively [119]. https://www.sciencedirect.com/science/article/pii/S1359645418305858


which probly explains why they are only used in small motors.

Table 2 - Applications for REEs in the emerging technology areas

Application	Examples	Rare-Earth-Elements
Light Weight Magnets	Cars Light weight magnets in motors for windows, windscreen wipers, starter motors, alternators, etc Electronics Magnets in disc drives for computers, data storage, portable music players (e.g. iPods), video recorders, consoles, video cameras Speakers Wind turbine	Nd, Pr, Sm, Dy, Tb
Catalyst	Automotive catalyst Clean diesel Oil refining	La, Ce, Nd, Pr, Sc
Hybrid vehicles	Electric motors and generators Hybrid batteries	Nd, Pr, Dy, TbLa, Nd, Ce
Compact fluorescent lights, energy saving lamps		Eu, Tb, Y, Sc
Polishing powders	TV and computer screensLCD, Plasma, CRT Optical lenses Precision optical and electronic components	Ce, La, Pr, Sc
Glass additives	CRT screensto stabilise glass from cathode ray Small optical lenses PhosphorsTV and computer screens	Ce, Er, Gd, Tb, La, Nd, Yb, Pm, Sc
Ceramics		Dy, Er, Pr, Gd, Ho, Ce, La

So, for the time being EVs use Nd, Pr, Dy, TbLa, Nd, Ce.

I think this research deserves the Ausheds PhD.