Question

A film with this property pins the top film of permalloy (“perm-alloy”) in valve-like devices used as hard-drive read heads. Doping the insulator LaMnO3 with calcium or strontium causes it to [emphasize] stop exhibiting this phenomenon and become highly conductive. The first conclusive evidence of a material exhibiting this phenomenon came from Clifford Shull and Samuel Smart’s neutron diffraction experiment. In an archetypal example of this phenomenon, it arises because d electrons partially occupy the antibonding orbital of a Mn–O–Mn chain, and thus the manganese (-5[1])ions can interact across oxygen via superexchange. Uniquely, chromium (-5[1])exhibits this phenomenon at room temperature. In (10[1])materials exhibiting this phenomenon, susceptibility (-5[1])increases (-5[1])with (-5[1])temperature up to the (10[1])Néel (“NAY-el”) temperature. (10[3]-5[2])For 10 points, (10[2])name this (10[1])phenomenon (-5[1])in which neighboring spins (-5[1])point in opposite directions. (10[4]-5[1])■END■ (10[4]0[7])

ANSWER: antiferromagnetism [or antiferromagnetic materials; prompt on magnetism or magnetic materials or materials with magnetic ordering; reject “ferromagnetism,” “diamagnetism,” “paramagnetism,” or any other more specific forms of magnetism] (The first sentence refers to spin valves.)
<Physics>
= Average correct buzz position

Summary

2023 ACF Nationals04/22/2023Y2273%0%45%119.00

Buzzes

PlayerTeamOpponentBuzz PositionValue
Adam FineChicago ACornell A83-5
Swapnil GargUC Berkeley AHarvard A92-5
Raul PassementTexas ANorth Carolina A9910
Dan NiCornell BChicago C104-5
Geoffrey WuColumbia AMIT A105-5
Alan XieYale BClaremont A106-5
Eric WolfsbergStanford AWUSTL A11010
Vivek SasseChicago BYale A112-5
David BassVirginia AMcGill A11210
S. A. ShenoyGeorgia Tech BPenn State A11210
Alex AkridgeIndiana AMinnesota A11210
Yash MandaviaIllinois AWUSTL B112-5
Sharath NarayanNorthwestern AToronto A11510
Arya KarthikGeorgia Tech AOhio State A11510
Jason HongBrown ADuke A11710
Rohan ShelkeUC Berkeley BMichigan A118-5
Maximillian NieburJohns Hopkins ARutgers B122-5
Geoffrey ChenCornell AChicago A12610
Daniel MaYale AChicago B12610
Connor BlakeChicago CCornell B12610
Tiffany ZhouFlorida BMinnesota B126-5
Joelle SmartRutgers AIowa State A12610
Albert ZhangColumbia BHouston A1270
Sean DoyleHouston AColumbia B1270
June YinWUSTL BIllinois A12710
Collin AceRutgers BJohns Hopkins A1270
Aidan FeinVanderbilt AImperial A1270
Michael MaysImperial AVanderbilt A1270
Isak JatoiSouth Carolina APenn A12710
Steven LiuMIT AColumbia A12710
Mazin OmerHarvard AUC Berkeley A12710
Todd MaslykMichigan AUC Berkeley B1270
Benjamin WeinerMinnesota BFlorida B1270