No.
Can you explain why? Technically I WOULD be using an evil weapon.
What about if I used a small demon/devil as an improvised weapon?
Creatures only overcome DR with their body/natural weapons if they possess the same DR.
So are you saying that my "weapon" needs to be able to overcome the DR with its body in order to overcome the DR when used AS a weapon? You know, that makes a lot of sense. Not 100% convinced that's RAW though
The SRD says
Some monsters are vulnerable to chaotic-, evil-, good-, or lawful-aligned weapons. When a cleric casts align weapon, affected weapons might gain one or more of these properties, and certain magic weapons have these properties as well. A creature with an alignment subtype (chaotic, evil, good, or lawful) can overcome this type of damage reduction with its natural weapons and weapons it wields as if the weapons or natural weapons had an alignment (or alignments) that match the subtype(s) of the creature.
So why isn't an evil halfling an evil aligned weapon? I mean it IS evil. It IS a weapon in that context....
For the same reason a sword made by an evil mage or usin dark sacrifice xp doesn't auto-overcome unless the appropriate buff spell is placed on it (Like ablackguard's curse weapon) or it has the proper weapon ehnacement property on it (holy/unholy/axiomatic/anarchic)
Alignment,subtypes, and weapon qualities are all unrelated in the game.
Edit: clearerexplanation - alignment, and alignment aligned are not the same. If I am lawfulgood, I am not lawful and good aligned, I am just lawful and good. It's why a monkdoesn't autobypass alignment DR it matches wih it's alignment.
Also, on my phone, so apologies for horrendous typing.